Merge branch 'main' into hasareej_LYN-2475_viewportui_switcher

Code/Framework/AzToolsFramework/AzToolsFramework/API/ToolsApplicationAPI.h

@@ -578,16 +578,6 @@ namespace AzToolsFramework
          */
         virtual bool IsEditorInIsolationMode() = 0;
 
-        /*!
-        * Get the engine root path that the current tool is running under.  
-        */
-        virtual const char* GetEngineRootPath() const = 0;
-
-        /**
-        * Get the version of the engine the current tools application is running under
-        */
-        virtual const char* GetEngineVersion() const = 0;
-
         /**
         * Creates and adds a new entity to the tools application from components which match at least one of the requiredTags
         * The tag matching occurs on AZ::Edit::SystemComponentTags attribute from the reflected class data in the serialization context
@@ -601,7 +591,7 @@ namespace AzToolsFramework
         virtual ResolveToolPathOutcome ResolveConfigToolsPath(const char* toolApplicationName) const = 0;
 
         /**
-         * LUMBERYARD INTERNAL USE ONLY.
+         * Open 3D Engine Internal use only.
          *
          * Run a specific redo command separate from the undo/redo system.
          * In many cases before a modifcation on an entity takes place, it is first packaged into 
@@ -825,8 +815,6 @@ namespace AzToolsFramework
         /// Hide or show the circular dependency error when saving slices
         virtual void SetShowCircularDependencyError(const bool& /*showCircularDependencyError*/) {}
 
-        virtual void SetEditTool(const char* /*tool*/) {}
-
         /// Launches the Lua editor and opens the specified (space separated) files.
         virtual void LaunchLuaEditor(const char* /*files*/) {}
 

Code/Framework/AzToolsFramework/AzToolsFramework/Application/ToolsApplication.cpp

@@ -92,7 +92,7 @@ namespace AzToolsFramework
     namespace Internal
     {
         static const char* s_engineConfigFileName = "engine.json";
-        static const char* s_engineConfigEngineVersionKey = "LumberyardVersion";
+        static const char* s_engineConfigEngineVersionKey = "O3DEVersion";
 
         static const char* s_startupLogWindow = "Startup";
 
@@ -224,112 +224,6 @@ namespace AzToolsFramework
 
     } // Internal
 
-#define AZ_MAX_ENGINE_VERSION_LEN   64
-    // Private Implementation class to manage the engine root and version
-    // Note: We are not using any AzCore classes because the ToolsApplication
-    // initialization happens early on, before the Allocators get instantiated,
-    // so we are using Qt privately instead
-    class ToolsApplication::EngineConfigImpl
-    {
-    private:
-        friend class ToolsApplication;
-
-        typedef QMap<QString, QString> EngineJsonMap;
-
-        EngineConfigImpl(const char* logWindow, const char* fileName)
-            : m_logWindow(logWindow)
-            , m_fileName(fileName)
-        {
-            m_engineRoot[0] = '\0';
-            m_engineVersion[0] = '\0';
-        }
-
-        char            m_engineRoot[AZ_MAX_PATH_LEN];
-        char            m_engineVersion[AZ_MAX_ENGINE_VERSION_LEN];
-        EngineJsonMap   m_engineConfigMap;
-        const char*     m_logWindow;
-        const char*     m_fileName;
-
-
-        // Read an engine configuration into a map of key/value pairs
-        bool ReadEngineConfigIntoMap(QString engineJsonPath, EngineJsonMap& engineJsonMap)
-        {
-            QFile engineJsonFile(engineJsonPath);
-            if (!engineJsonFile.open(QIODevice::ReadOnly | QIODevice::Text))
-            {
-                AZ_Warning(m_logWindow, false, "Unable to open file '%s' in the current root directory", engineJsonPath.toUtf8().data());
-                return false;
-            }
-
-            QByteArray engineJsonData = engineJsonFile.readAll();
-            engineJsonFile.close();
-            QJsonDocument engineJsonDoc(QJsonDocument::fromJson(engineJsonData));
-            if (engineJsonDoc.isNull())
-            {
-                AZ_Warning(m_logWindow, false, "Unable to read file '%s' in the current root directory", engineJsonPath.toUtf8().data());
-                return false;
-            }
-
-            QJsonObject engineJsonRoot = engineJsonDoc.object();
-            for (const QString& configKey : engineJsonRoot.keys())
-            {
-                QJsonValue configValue = engineJsonRoot[configKey];
-                if (configValue.isString() || configValue.isDouble())
-                {
-                    // Only map strings and numbers, ignore every other type
-                    engineJsonMap[configKey] = configValue.toString();
-                }
-                else
-                {
-                    AZ_Warning(m_logWindow, false, "Ignoring key '%s' from '%s', unsupported type.", configKey.toUtf8().data(), engineJsonPath.toUtf8().data());
-                }
-            }
-            return true;
-        }
-
-        // Initialize the engine config object based on the current
-        bool Initialize(const char* currentEngineRoot)
-        {
-            // Start with the app root as the engine root (legacy), but check to see if the engine root
-            // is external to the app root
-            azstrncpy(m_engineRoot, AZ_ARRAY_SIZE(m_engineRoot), currentEngineRoot, strlen(currentEngineRoot) + 1);
-
-            // From the appRoot, check and see if we can read any external engine reference in engine.json
-            QString engineJsonFileName = QString(m_fileName);
-            QString engineJsonFilePath = QDir(currentEngineRoot).absoluteFilePath(engineJsonFileName);
-
-            // From the appRoot, check and see if we can read any external engine reference in engine.json
-            if (!QFile::exists(engineJsonFilePath))
-            {
-                AZ_Warning(m_logWindow, false, "Unable to find '%s' in the current app root directory.", m_fileName);
-                return false;
-            }
-            if (!ReadEngineConfigIntoMap(engineJsonFilePath, m_engineConfigMap))
-            {
-                AZ_Warning(m_logWindow, false, "Defaulting root engine path to '%s'", currentEngineRoot);
-                return false;
-            }
-
-            // Read in the local engine version value
-            auto localEngineVersionValue = m_engineConfigMap.find(QString(AzToolsFramework::Internal::s_engineConfigEngineVersionKey));
-            QString localEngineVersion(localEngineVersionValue.value());
-            azstrncpy(m_engineVersion, AZ_ARRAY_SIZE(m_engineVersion), localEngineVersion.toUtf8().data(), localEngineVersion.length() + 1);
-
-            return true;
-        }
-
-        const char* GetEngineRoot() const
-        {
-            return m_engineRoot;
-        }
-
-        const char* GetEngineVersion() const
-        {
-            return m_engineVersion;
-        }
-    };
-
-
     ToolsApplication::ToolsApplication(int* argc, char*** argv)
         : AzFramework::Application(argc, argv)
         , m_selectionBounds(AZ::Aabb())
@@ -339,7 +233,6 @@ namespace AzToolsFramework
         , m_isInIsolationMode(false)
     {
         ToolsApplicationRequests::Bus::Handler::BusConnect();
-        m_engineConfigImpl.reset(new ToolsApplication::EngineConfigImpl(AzToolsFramework::Internal::s_startupLogWindow, AzToolsFramework::Internal::s_engineConfigFileName));
 
         m_undoCache.RegisterToUndoCacheInterface();
     }
@@ -391,7 +284,6 @@ namespace AzToolsFramework
     void ToolsApplication::Start(const Descriptor& descriptor, const StartupParameters& startupParameters/* = StartupParameters()*/)
     {
         Application::Start(descriptor, startupParameters);
-        InitializeEngineConfig();
 
         m_editorEntityManager.Start();
 
@@ -399,14 +291,6 @@ namespace AzToolsFramework
         AZ_Assert(m_editorEntityAPI, "ToolsApplication - Could not retrieve instance of EditorEntityAPI");
     }
 
-    void ToolsApplication::InitializeEngineConfig()
-    {
-        if (!m_engineConfigImpl->Initialize(GetEngineRoot()))
-        {
-            AZ_Warning(AzToolsFramework::Internal::s_startupLogWindow, false, "Defaulting engine root path to '%s'", GetEngineRoot());
-        }
-    }
-
     void ToolsApplication::StartCommon(AZ::Entity* systemEntity)
     {
         Application::StartCommon(systemEntity);
@@ -1832,16 +1716,6 @@ namespace AzToolsFramework
         return m_isInIsolationMode;
     }
 
-    const char* ToolsApplication::GetEngineRootPath() const
-    {
-        return m_engineConfigImpl->GetEngineRoot();
-    }
-
-    const char* ToolsApplication::GetEngineVersion() const
-    {
-        return m_engineConfigImpl->GetEngineVersion();
-    }
-
     void ToolsApplication::CreateAndAddEntityFromComponentTags(const AZStd::vector<AZ::Crc32>& requiredTags, const char* entityName)
     {
         if (!entityName || !entityName[0])

Code/Framework/AzToolsFramework/AzToolsFramework/Application/ToolsApplication.h

@@ -150,12 +150,10 @@ namespace AzToolsFramework
         void EnterEditorIsolationMode() override;
         void ExitEditorIsolationMode() override;
         bool IsEditorInIsolationMode() override;
-        const char* GetEngineRootPath() const override;
-        const char* GetEngineVersion() const override;
 
         void CreateAndAddEntityFromComponentTags(const AZStd::vector<AZ::Crc32>& requiredTags, const char* entityName) override;
 
-        /* LUMBERYARD INTERNAL USE ONLY. */
+        /* Open 3D Engine INTERNAL USE ONLY. */
         void RunRedoSeparately(UndoSystem::URSequencePoint* redoCommand) override;
 
         //////////////////////////////////////////////////////////////////////////
@@ -174,7 +172,6 @@ namespace AzToolsFramework
 
         void CreateUndosForDirtyEntities();
         void ConsistencyCheckUndoCache();
-        void InitializeEngineConfig();
         AZ::Aabb                            m_selectionBounds;
         EntityIdList                        m_selectedEntities;
         EntityIdList                        m_highlightedEntities;
@@ -186,9 +183,6 @@ namespace AzToolsFramework
         bool                                m_isInIsolationMode;
         EntityIdSet                         m_isolatedEntityIdSet;
 
-        class EngineConfigImpl;
-        AZStd::unique_ptr<EngineConfigImpl> m_engineConfigImpl;
-
         EditorEntityAPI* m_editorEntityAPI = nullptr;
 
         EditorEntityManager m_editorEntityManager;

Code/Framework/AzToolsFramework/AzToolsFramework/Asset/AssetUtils.cpp

@@ -255,10 +255,8 @@ namespace AzToolsFramework::AssetUtils
         return configFiles;
     }
 
-    bool UpdateFilePathToCorrectCase(const QString& root, QString& relativePathFromRoot)
+    bool UpdateFilePathToCorrectCase(AZStd::string_view rootPath, AZStd::string& relPathFromRoot)
     {
-        AZStd::string rootPath(root.toUtf8().data());
-        AZStd::string relPathFromRoot(relativePathFromRoot.toUtf8().data());
         AZ::StringFunc::Path::Normalize(relPathFromRoot);
         AZStd::vector<AZStd::string> tokens;
         AZ::StringFunc::Tokenize(relPathFromRoot.c_str(), tokens, AZ_CORRECT_FILESYSTEM_SEPARATOR_STRING);
@@ -321,7 +319,6 @@ namespace AzToolsFramework::AssetUtils
         {
             relPathFromRoot.clear();
             AZ::StringFunc::Join(relPathFromRoot, tokens.begin(), tokens.end(), AZ_CORRECT_FILESYSTEM_SEPARATOR_STRING);
-            relativePathFromRoot = relPathFromRoot.c_str();
         }
 
         return success;

Code/Framework/AzToolsFramework/AzToolsFramework/Asset/AssetUtils.h

@@ -52,5 +52,5 @@ namespace AzToolsFramework::AssetUtils
     //!        which will be normalized and updated to be correct casing.
     //! @return if such a file does NOT exist, it returns FALSE, else returns TRUE.
     //! @note A very expensive function!  Call sparingly.
-    bool UpdateFilePathToCorrectCase(const QString& root, QString& relativePathFromRoot);
+    bool UpdateFilePathToCorrectCase(AZStd::string_view root, AZStd::string& relativePathFromRoot);
 } //namespace AzToolsFramework::AssetUtils

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/AssetPicker/AssetPickerDialog.cpp

@@ -23,7 +23,7 @@
 #include <AzToolsFramework/AssetBrowser/AssetPicker/AssetPickerDialog.h>
 
 AZ_PUSH_DISABLE_WARNING(4251 4244, "-Wunknown-warning-option") // disable warnings spawned by QT
-#include "AssetBrowser/AssetPicker/ui_AssetPickerDialog.h"
+#include <AzToolsFramework/AssetBrowser/AssetPicker/ui_AssetPickerDialog.h>
 #include <QPushButton>
 #include <QDialogButtonBox>
 #include <QKeyEvent>

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Previewer/EmptyPreviewer.cpp

@@ -17,7 +17,7 @@
 // 4251: class needs to have dll-interface to be used by clients of class 
 // 4800: forcing value to bool 'true' or 'false' (performance warning)
 AZ_PUSH_DISABLE_WARNING(4251 4800, "-Wunknown-warning-option")
-#include "AssetBrowser/Previewer/ui_EmptyPreviewer.h"
+#include <AzToolsFramework/AssetBrowser/Previewer/ui_EmptyPreviewer.h>
 AZ_POP_DISABLE_WARNING
 
 namespace AzToolsFramework
@@ -45,4 +45,4 @@ namespace AzToolsFramework
     }
 }
 
-#include <AssetBrowser/Previewer/moc_EmptyPreviewer.cpp>
+#include <AssetBrowser/Previewer/moc_EmptyPreviewer.cpp>

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Search/FilterByWidget.cpp

@@ -11,7 +11,7 @@
 */
 #include <AzQtComponents/Components/ExtendedLabel.h>
 AZ_PUSH_DISABLE_WARNING(4251, "-Wunknown-warning-option") // 4251: class 'QFlags<Qt::AlignmentFlag>' needs to have dll-interface to be used by clients of class 'QLayoutItem'
-#include <AssetBrowser/Search/ui_FilterByWidget.h>
+#include <AzToolsFramework/AssetBrowser/Search/ui_FilterByWidget.h>
 AZ_POP_DISABLE_WARNING
 #include <AzToolsFramework/AssetBrowser/Search/FilterByWidget.h>
 
@@ -39,4 +39,4 @@ namespace AzToolsFramework
     } // namespace AssetBrowser
 } // namespace AzToolsFramework
 
-#include "AssetBrowser/Search/moc_FilterByWidget.cpp"
+#include "AssetBrowser/Search/moc_FilterByWidget.cpp"

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Search/SearchAssetTypeSelectorWidget.cpp

@@ -18,7 +18,7 @@
 #include <AzToolsFramework/AssetBrowser/Search/FilterByWidget.h>
 
 AZ_PUSH_DISABLE_WARNING(4251, "-Wunknown-warning-option") // 4251: 'QLayoutItem::align': class 'QFlags<Qt::AlignmentFlag>' needs to have dll-interface to be used by clients of class 'QLayoutItem'
-#include <AssetBrowser/Search/ui_SearchAssetTypeSelectorWidget.h>
+#include <AzToolsFramework/AssetBrowser/Search/ui_SearchAssetTypeSelectorWidget.h>
 AZ_POP_DISABLE_WARNING
 
 #include <QPushButton>
@@ -154,4 +154,4 @@ namespace AzToolsFramework
     } // namespace AssetBrowser
 } // namespace AzToolsFramework
 
-#include "AssetBrowser/Search/moc_SearchAssetTypeSelectorWidget.cpp"
+#include "AssetBrowser/Search/moc_SearchAssetTypeSelectorWidget.cpp"

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Search/SearchParametersWidget.cpp

@@ -12,7 +12,7 @@
 
 #include "SearchParametersWidget.h"
 AZ_PUSH_DISABLE_WARNING(4251, "-Wunknown-warning-option") // 4251: 'QLayoutItem::align': class 'QFlags<Qt::AlignmentFlag>' needs to have dll-interface to be used by clients of class 'QLayoutItem'
-#include "AssetBrowser/Search/ui_SearchParametersWidget.h"
+#include <AzToolsFramework/AssetBrowser/Search/ui_SearchParametersWidget.h>
 AZ_POP_DISABLE_WARNING
 #include <AzQtComponents/Components/ExtendedLabel.h>
 
@@ -68,4 +68,4 @@ namespace AzToolsFramework
     } // namespace AssetBrowser
 } // namespace AzToolsFramework
 
-#include "AssetBrowser/Search/moc_SearchParametersWidget.cpp"
+#include "AssetBrowser/Search/moc_SearchParametersWidget.cpp"

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Search/SearchWidget.cpp

@@ -170,6 +170,15 @@ namespace AzToolsFramework
             return m_filter;
         }
 
+        QSharedPointer<CompositeFilter> SearchWidget::GetStringFilter() const
+        {
+            return m_stringFilter;
+        }
+
+        QSharedPointer<CompositeFilter> SearchWidget::GetTypesFilter() const
+        {
+            return m_typesFilter;
+        }
     } // namespace AssetBrowser
 } // namespace AzToolsFramework
 

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Search/SearchWidget.h

@@ -39,6 +39,10 @@ namespace AzToolsFramework
 
             QSharedPointer<CompositeFilter> GetFilter() const;
 
+            QSharedPointer<CompositeFilter> GetStringFilter() const;
+
+            QSharedPointer<CompositeFilter> GetTypesFilter() const;
+
             QString GetFilterString() const { return textFilter(); }
             void ClearStringFilter() { ClearTextFilter(); }
 

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Views/AssetBrowserTreeView.h

@@ -54,7 +54,7 @@ namespace AzToolsFramework
             //! Set unique asset browser name, used to persist tree expansion states
             void SetName(const QString& name);
 
-            // LUMBERYARD_DEPRECATED
+            // O3DE_DEPRECATED
             void LoadState(const QString& name);
             void SaveState() const;
 

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Views/EntryDelegate.cpp

@@ -140,7 +140,7 @@ namespace AzToolsFramework
             else
             {
                 QPixmap pixmap = thumbnail->GetPixmap(size);
-                painter->drawPixmap(point.x(), point.y(), size.width(), size.height(), pixmap);
+                painter->drawPixmap(point, pixmap.scaled(size, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
             }
             return m_iconSize;
         }

Code/Framework/AzToolsFramework/AzToolsFramework/AssetEditor/AssetEditorWidget.cpp

@@ -19,9 +19,9 @@
 #include <AssetEditor/AssetEditorBus.h>
 #include <AssetEditor/AssetEditorHeader.h>
 AZ_PUSH_DISABLE_WARNING(4251, "-Wunknown-warning-option") // 'QLayoutItem::align': class 'QFlags<Qt::AlignmentFlag>' needs to have dll-interface to be used by clients of class 'QLayoutItem'
-#include <AssetEditor/ui_AssetEditorToolbar.h>
+#include <AzToolsFramework/AssetEditor/ui_AssetEditorToolbar.h>
 AZ_POP_DISABLE_WARNING
-#include <AssetEditor/ui_AssetEditorStatusBar.h>
+#include <AzToolsFramework/AssetEditor/ui_AssetEditorStatusBar.h>
 
 #include <AssetBrowser/AssetSelectionModel.h>
 
@@ -256,6 +256,8 @@ namespace AzToolsFramework
 
             m_userSettings = AZ::UserSettings::CreateFind<AssetEditorWidgetUserSettings>(k_assetEditorWidgetSettings, AZ::UserSettings::CT_LOCAL);
 
+            UpdateRecentFileListState();
+
             QObject::connect(m_recentFileMenu, &QMenu::aboutToShow, this, &AssetEditorWidget::PopulateRecentMenu);
         }
 
@@ -952,7 +954,8 @@ namespace AzToolsFramework
 
         void AssetEditorWidget::AddRecentPath(const AZStd::string& recentPath)
         {
-            m_userSettings->AddRecentPath(recentPath);            
+            m_userSettings->AddRecentPath(recentPath);
+            UpdateRecentFileListState();
         }
 
         void AssetEditorWidget::PopulateRecentMenu()
@@ -989,6 +992,21 @@ namespace AzToolsFramework
             m_saveAsAssetAction->setEnabled(true);
         }
 
+        void AssetEditorWidget::UpdateRecentFileListState()
+        {
+            if (m_recentFileMenu)
+            {
+                if (!m_userSettings || m_userSettings->m_recentPaths.empty())
+                {
+                    m_recentFileMenu->setEnabled(false);
+                }
+                else
+                {
+                    m_recentFileMenu->setEnabled(true);
+                }
+            }
+        }
+
     } // namespace AssetEditor
 } // namespace AzToolsFramework
 

Code/Framework/AzToolsFramework/AzToolsFramework/AssetEditor/AssetEditorWidget.h

@@ -122,6 +122,8 @@ namespace AzToolsFramework
             void OnCatalogAssetAdded(const AZ::Data::AssetId& assetId) override;
             void OnCatalogAssetRemoved(const AZ::Data::AssetId& assetId, const AZ::Data::AssetInfo& assetInfo) override;
 
+            void UpdateRecentFileListState();
+
         private:
             void DirtyAsset();
 

Code/Framework/AzToolsFramework/AzToolsFramework/Component/EditorComponentAPIComponent.cpp

@@ -191,10 +191,17 @@ namespace AzToolsFramework
                         {
                             if (componentClass->m_editData->m_name == componentTypeNames[i])
                             {
+                                // Although it is rare, it can happen that two (or more) components can have the same name.
+                                // We should only count the first occurrence, so that none of the names in componentTypeNames
+                                // get skipped, but whichever component type that is encountered last will be the one
+                                // that is captured in order to preserve the pre-existing behavior.
+                                if (foundTypeIds[i].IsNull())
+                                {
+                                    ++counter;
+                                }
+
                                 foundTypeIds[i] = componentClass->m_typeId;
-                                ++counter;
-                                //Although it is rare, it can happen that two components can have the same name.
-                                //We will capture only the first occurrence.
+
                                 return true;
                             }
                         }

Code/Framework/AzToolsFramework/AzToolsFramework/Debug/TraceContextBufferedFormatter.cpp

@@ -130,7 +130,7 @@ namespace AzToolsFramework
             int written = uuid.ToString(buffer, aznumeric_caster(bufferSize), false);
             if (written > 0)
             {
-                if (bufferSize - written > 0)
+                if (bufferSize > written)
                 {
                     buffer[written - 1] = '\n';
                     buffer[written] = 0;

Code/Framework/AzToolsFramework/AzToolsFramework/Entity/EditorEntityContextComponent.cpp

@@ -453,6 +453,7 @@ namespace AzToolsFramework
         {
             loadedSuccessfully = static_cast<PrefabEditorEntityOwnershipService*>(m_entityOwnershipService.get())->LoadFromStream(
                 stream, AZStd::string_view(levelPakFile.toUtf8(), levelPakFile.size()) );
+
         }
         
         LoadFromStreamComplete(loadedSuccessfully);
@@ -490,6 +491,14 @@ namespace AzToolsFramework
 
         EditorEntityContextNotificationBus::Broadcast(&EditorEntityContextNotification::OnStartPlayInEditorBegin);
 
+        //cache the current selected entities.
+        ToolsApplicationRequests::Bus::BroadcastResult(m_selectedBeforeStartingGame, &ToolsApplicationRequests::GetSelectedEntities);
+        //deselect entities if selected when entering game mode before deactivating the entities in StartPlayInEditor(...)
+        if (!m_selectedBeforeStartingGame.empty())
+        {
+            ToolsApplicationRequests::Bus::Broadcast(&ToolsApplicationRequests::MarkEntitiesDeselected, m_selectedBeforeStartingGame);
+        }
+
         if (m_isLegacySliceService)
         {
             SliceEditorEntityOwnershipService* editorEntityOwnershipService =
@@ -506,8 +515,6 @@ namespace AzToolsFramework
 
         m_isRunningGame = true;
 
-        ToolsApplicationRequests::Bus::BroadcastResult(m_selectedBeforeStartingGame, &ToolsApplicationRequests::GetSelectedEntities);
-
         EditorEntityContextNotificationBus::Broadcast(&EditorEntityContextNotification::OnStartPlayInEditor);
     }
 

Code/Framework/AzToolsFramework/AzToolsFramework/Entity/EditorEntityHelpers.cpp

@@ -136,6 +136,48 @@ namespace AzToolsFramework
         return entity->GetName();
     }
 
+    EntityList EntityIdListToEntityList(const EntityIdList& inputEntityIds)
+    {
+        EntityList entities;
+        entities.reserve(inputEntityIds.size());
+
+        for (AZ::EntityId entityId : inputEntityIds)
+        {
+            if (!entityId.IsValid())
+            {
+                continue;
+            }
+
+            if (auto entity = GetEntityById(entityId))
+            {
+                entities.emplace_back(entity);
+            }
+        }
+
+        return entities;
+    }
+
+    EntityList EntityIdSetToEntityList(const EntityIdSet& inputEntityIds)
+    {
+        EntityList entities;
+        entities.reserve(inputEntityIds.size());
+
+        for (AZ::EntityId entityId : inputEntityIds)
+        {
+            if (!entityId.IsValid())
+            {
+                continue;
+            }
+
+            if (auto entity = GetEntityById(entityId))
+            {
+                entities.emplace_back(entity);
+            }
+        }
+
+        return entities;
+    }
+
     void GetAllComponentsForEntity(const AZ::Entity* entity, AZ::Entity::ComponentArrayType& componentsOnEntity)
     {
         if (entity)
@@ -1068,6 +1110,45 @@ namespace AzToolsFramework
         return !allEntityClonesContainer.m_entities.empty();
     }
 
+    EntityIdSet GetCulledEntityHierarchy(const EntityIdList& entities)
+    {
+        EntityIdSet culledEntities;
+
+        for (const AZ::EntityId& entityId : entities)
+        {
+            bool selectionIncludesTransformHeritage = false;
+            AZ::EntityId parentEntityId = entityId;
+            do
+            {
+                AZ::EntityId nextParentId;
+                AZ::TransformBus::EventResult(
+                    /*result*/ nextParentId,
+                    /*address*/ parentEntityId,
+                    &AZ::TransformBus::Events::GetParentId);
+                parentEntityId = nextParentId;
+                if (!parentEntityId.IsValid())
+                {
+                    break;
+                }
+                for (const AZ::EntityId& parentCheck : entities)
+                {
+                    if (parentCheck == parentEntityId)
+                    {
+                        selectionIncludesTransformHeritage = true;
+                        break;
+                    }
+                }
+            } while (parentEntityId.IsValid() && !selectionIncludesTransformHeritage);
+
+            if (!selectionIncludesTransformHeritage)
+            {
+                culledEntities.insert(entityId);
+            }
+        }
+
+        return culledEntities;
+    }
+
     namespace Internal
     {
         void CloneSliceEntitiesAndChildren(

Code/Framework/AzToolsFramework/AzToolsFramework/Entity/EditorEntityHelpers.h

@@ -47,6 +47,9 @@ namespace AzToolsFramework
 
     AZStd::string GetEntityName(const AZ::EntityId& entityId, const AZStd::string_view& nameOverride = {});
 
+    EntityList EntityIdListToEntityList(const EntityIdList& inputEntityIds);
+    EntityList EntityIdSetToEntityList(const EntityIdSet& inputEntityIds);
+
     template <typename... ComponentTypes>
     struct AddComponents
     {
@@ -202,4 +205,8 @@ namespace AzToolsFramework
     /// Wrap EBus SetSelectedEntities call.
     void SelectEntities(const AzToolsFramework::EntityIdList& entities);
 
+    /// Return a set of entities, culling any that have an ancestor in the list.
+    /// e.g. This is useful for getting a concise set of entities that need to be duplicated.
+    EntityIdSet GetCulledEntityHierarchy(const EntityIdList& entities);
+
 }; // namespace AzToolsFramework

Code/Framework/AzToolsFramework/AzToolsFramework/Entity/EditorEntityModel.cpp

@@ -707,7 +707,7 @@ namespace AzToolsFramework
     {
         QMessageBox::warning(AzToolsFramework::GetActiveWindow(),
             QStringLiteral("Can't instantiate the selected slice"),
-            QString("The slice may contain UI elements that can't be instantiated in the main Lumberyard editor. "
+            QString("The slice may contain UI elements that can't be instantiated in the main Open 3D Engine editor. "
                 "Use the UI Editor to instantiate this slice or select another one."),
             QMessageBox::Ok);
     }

Code/Framework/AzToolsFramework/AzToolsFramework/Entity/PrefabEditorEntityOwnershipService.cpp

@@ -11,8 +11,10 @@
 */
 
 #include <AzCore/Component/Entity.h>
+#include <AzCore/Component/TransformBus.h>
 #include <AzCore/Script/ScriptSystemBus.h>
 #include <AzFramework/API/ApplicationAPI.h>
+#include <AzFramework/Entity/GameEntityContextBus.h>
 #include <AzFramework/Spawnable/RootSpawnableInterface.h>
 #include <AzToolsFramework/API/ToolsApplicationAPI.h>
 #include <AzToolsFramework/Entity/PrefabEditorEntityOwnershipService.h>
@@ -21,6 +23,7 @@
 #include <AzToolsFramework/Prefab/PrefabDomUtils.h>
 #include <AzToolsFramework/Prefab/PrefabLoader.h>
 #include <AzToolsFramework/Prefab/PrefabSystemComponentInterface.h>
+#include <AzToolsFramework/Prefab/PrefabUndoHelpers.h>
 
 namespace AzToolsFramework
 {
@@ -91,23 +94,48 @@ namespace AzToolsFramework
             m_prefabSystemComponent->RemoveTemplate(templateId);
         }
         m_rootInstance->Reset();
+        m_rootInstance->SetContainerEntityName("Level");
+
+        AzFramework::EntityOwnershipServiceNotificationBus::Event(
+            m_entityContextId, &AzFramework::EntityOwnershipServiceNotificationBus::Events::OnEntityOwnershipServiceReset);
     }
 
     void PrefabEditorEntityOwnershipService::AddEntity(AZ::Entity* entity)
     {
         AZ_Assert(IsInitialized(), "Tried to add an entity without initializing the Entity Ownership Service");
+        ScopedUndoBatch undoBatch("Undo adding entity");
+        Prefab::PrefabDom instanceDomBeforeUpdate;
+        Prefab::PrefabDomUtils::StoreInstanceInPrefabDom(*m_rootInstance, instanceDomBeforeUpdate);
+
         m_rootInstance->AddEntity(*entity);
         HandleEntitiesAdded({ entity });
+        AZ::TransformBus::Event(entity->GetId(), &AZ::TransformInterface::SetParent, m_rootInstance->m_containerEntity->GetId());
+
+        Prefab::PrefabUndoHelpers::UpdatePrefabInstance(
+            *m_rootInstance, "Undo adding entity", instanceDomBeforeUpdate, undoBatch.GetUndoBatch());
     }
 
     void PrefabEditorEntityOwnershipService::AddEntities(const EntityList& entities)
     {
         AZ_Assert(IsInitialized(), "Tried to add entities without initializing the Entity Ownership Service");
+        ScopedUndoBatch undoBatch("Undo adding entities");
+        Prefab::PrefabDom instanceDomBeforeUpdate;
+        Prefab::PrefabDomUtils::StoreInstanceInPrefabDom(*m_rootInstance, instanceDomBeforeUpdate);
+
         for (AZ::Entity* entity : entities)
         {
             m_rootInstance->AddEntity(*entity);
         }
+
         HandleEntitiesAdded(entities);
+
+        for (AZ::Entity* entity : entities)
+        {
+            AZ::TransformBus::Event(entity->GetId(), &AZ::TransformInterface::SetParent, m_rootInstance->m_containerEntity->GetId());
+        }
+
+        Prefab::PrefabUndoHelpers::UpdatePrefabInstance(
+            *m_rootInstance, "Undo adding entities", instanceDomBeforeUpdate, undoBatch.GetUndoBatch());
     }
 
     bool PrefabEditorEntityOwnershipService::DestroyEntity(AZ::Entity* entity)
@@ -171,7 +199,9 @@ namespace AzToolsFramework
 
         m_rootInstance->SetTemplateId(templateId);
         m_rootInstance->SetTemplateSourcePath(m_loaderInterface->GetRelativePathToProject(filename));
+        m_rootInstance->SetContainerEntityName("Level");
         m_prefabSystemComponent->PropagateTemplateChanges(templateId);
+
         return true;
     }
 
@@ -251,18 +281,29 @@ namespace AzToolsFramework
         AZStd::unique_ptr<Prefab::Instance> createdPrefabInstance =
             m_prefabSystemComponent->CreatePrefab(entities, AZStd::move(nestedPrefabInstances), filePath);
 
-        if (!instanceToParentUnder)
-        {
-            instanceToParentUnder = *m_rootInstance;
-        }
-
         if (createdPrefabInstance)
         {
+            if (!instanceToParentUnder)
+            {
+                instanceToParentUnder = *m_rootInstance;
+            }
+
             Prefab::Instance& addedInstance = instanceToParentUnder->get().AddInstance(AZStd::move(createdPrefabInstance));
-            HandleEntitiesAdded({addedInstance.m_containerEntity.get()});
+            AZ::Entity* containerEntity = addedInstance.m_containerEntity.get();
+            containerEntity->AddComponent(aznew Prefab::EditorPrefabComponent());
+            HandleEntitiesAdded({containerEntity});
+            HandleEntitiesAdded(entities);
+            
+            // Update the template of the instance since we modified the entities of the instance by calling HandleEntitiesAdded.
+            Prefab::PrefabDom serializedInstance;
+            if (Prefab::PrefabDomUtils::StoreInstanceInPrefabDom(addedInstance, serializedInstance))
+            {
+                m_prefabSystemComponent->UpdatePrefabTemplate(addedInstance.GetTemplateId(), serializedInstance);
+            }
+            
             return addedInstance;
         }
-        HandleEntitiesAdded(entities);
+
         return AZStd::nullopt;
     }
 
@@ -295,6 +336,9 @@ namespace AzToolsFramework
 
     void PrefabEditorEntityOwnershipService::StartPlayInEditor()
     {
+        // This is a workaround until the replacement for GameEntityContext is done
+        AzFramework::GameEntityContextEventBus::Broadcast(&AzFramework::GameEntityContextEventBus::Events::OnPreGameEntitiesStarted);
+
         if (m_rootInstance && !m_playInEditorData.m_isEnabled)
         {
             // Construct the runtime entities and products 
@@ -339,11 +383,16 @@ namespace AzToolsFramework
                             m_playInEditorData.m_assets.emplace_back(product.ReleaseAsset().release(), AZ::Data::AssetLoadBehavior::Default);
                         }
 
+
                         if (rootSpawnableIndex != NoRootSpawnable)
                         {
                             m_playInEditorData.m_entities.Reset(m_playInEditorData.m_assets[rootSpawnableIndex]);
                             m_playInEditorData.m_entities.SpawnAllEntities();
                         }
+
+                        // This is a workaround until the replacement for GameEntityContext is done
+                        AzFramework::GameEntityContextEventBus::Broadcast(
+                            &AzFramework::GameEntityContextEventBus::Events::OnGameEntitiesStarted);
                     }
                     else
                     {
@@ -402,6 +451,9 @@ namespace AzToolsFramework
                     AZ::ScriptSystemRequestBus::Broadcast(&AZ::ScriptSystemRequests::GarbageCollect);
                 });
             m_playInEditorData.m_entities.Clear();
+
+            // This is a workaround until the replacement for GameEntityContext is done
+            AzFramework::GameEntityContextEventBus::Broadcast(&AzFramework::GameEntityContextEventBus::Events::OnGameEntitiesReset);
         }
 
         m_playInEditorData.m_isEnabled = false;

Code/Framework/AzToolsFramework/AzToolsFramework/Entity/PrefabEditorEntityOwnershipService.h

@@ -186,7 +186,7 @@ namespace AzToolsFramework
         PlayInEditorData m_playInEditorData;
 
         //////////////////////////////////////////////////////////////////////////
-        // PrefabSystemComponentInterface interface implementation
+        // PrefabEditorEntityOwnershipInterface implementation
         Prefab::InstanceOptionalReference CreatePrefab(
             const AZStd::vector<AZ::Entity*>& entities, AZStd::vector<AZStd::unique_ptr<Prefab::Instance>>&& nestedPrefabInstances,
             AZ::IO::PathView filePath, Prefab::InstanceOptionalReference instanceToParentUnder) override;

Code/Framework/AzToolsFramework/AzToolsFramework/Manipulators/ManipulatorManager.h

@@ -89,7 +89,7 @@ namespace AzToolsFramework
             const AzFramework::CameraState& cameraState,
             const ViewportInteraction::MouseInteraction& mouseInteraction);
 
-        // LUMBERYARD_DEPRECATED(LY-117150)
+        // O3DE_DEPRECATED(LY-117150)
         /// Check if the modifier key state has changed - if so we may need to refresh
         /// certain manipulator bounds.
         AZ_DEPRECATED(

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/EditorPrefabComponent.cpp

@@ -56,16 +56,6 @@ namespace AzToolsFramework
 
         void EditorPrefabComponent::Activate()
         {
-            PrefabPublicInterface* prefabPublicInterface = AZ::Interface<PrefabPublicInterface>::Get();
-            if (prefabPublicInterface && prefabPublicInterface->IsLevelInstanceContainerEntity(GetEntityId()))
-            {
-                EntityOutlinerWidgetInterface* entityOutlinerWidgetInterface = AZ::Interface<EntityOutlinerWidgetInterface>::Get();
-                if (entityOutlinerWidgetInterface)
-                {
-                    entityOutlinerWidgetInterface->SetRootEntity(GetEntityId());
-                }
-            }
-
             PrefabInstanceContainerNotificationBus::Broadcast(
                 &PrefabInstanceContainerNotifications::OnPrefabComponentActivate, GetEntityId());
         }

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/Instance.cpp

@@ -123,7 +123,11 @@ namespace AzToolsFramework
         void Instance::SetTemplateSourcePath(AZ::IO::PathView sourcePath)
         {
             m_templateSourcePath = sourcePath;
-            m_containerEntity->SetName(sourcePath.Filename().Native());
+        }
+
+        void Instance::SetContainerEntityName(AZStd::string_view containerName)
+        {
+            m_containerEntity->SetName(containerName);
         }
 
         bool Instance::AddEntity(AZ::Entity& entity)
@@ -154,7 +158,7 @@ namespace AzToolsFramework
             if (instanceToTemplateEntityIdIterator != m_instanceToTemplateEntityIdMap.end())
             {
                 entityAliasToRemove = instanceToTemplateEntityIdIterator->second;
-                bool isEntityRemoved = m_instanceEntityMapper->UnregisterEntity(entityId) &&
+                [[maybe_unused]] bool isEntityRemoved = m_instanceEntityMapper->UnregisterEntity(entityId) &&
                     m_templateToInstanceEntityIdMap.erase(entityAliasToRemove) && m_instanceToTemplateEntityIdMap.erase(entityId);
                 AZ_Assert(isEntityRemoved,
                     "Prefab - Failed to remove entity with id %s with a Prefab Instance derived from source asset %s "
@@ -563,7 +567,7 @@ namespace AzToolsFramework
 
         AZ::EntityId Instance::GetContainerEntityId() const
         {
-            return m_containerEntity->GetId();
+            return m_containerEntity ? m_containerEntity->GetId() : AZ::EntityId();
         }
 
         bool Instance::HasContainerEntity() const

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/Instance.h

@@ -80,6 +80,7 @@ namespace AzToolsFramework
 
             const AZ::IO::Path& GetTemplateSourcePath() const;
             void SetTemplateSourcePath(AZ::IO::PathView sourcePath);
+            void SetContainerEntityName(AZStd::string_view containerName);
 
             bool AddEntity(AZ::Entity& entity);
             bool AddEntity(AZ::Entity& entity, EntityAlias entityAlias);

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/InstanceEntityScrubber.h

@@ -31,7 +31,7 @@ namespace AzToolsFramework
         class InstanceEntityScrubber
         {
         public:
-            AZ_RTTI(InstanceEntityScrubber, "{0BC12562-C240-48AD-89C6-EDF572C9B485}");
+            AZ_TYPE_INFO(InstanceEntityScrubber, "{0BC12562-C240-48AD-89C6-EDF572C9B485}");
 
             explicit InstanceEntityScrubber(Instance::EntityList& entities);
 

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/InstanceSerializer.cpp

@@ -209,7 +209,7 @@ namespace AzToolsFramework
             EntityList entitiesInInstance;
             entitiesInInstance.reserve(instance->m_entities.size() + 1);
 
-            if (instance->m_containerEntity->GetId().IsValid())
+            if (instance->m_containerEntity && instance->m_containerEntity->GetId().IsValid())
             {
                 entitiesInInstance.emplace_back(instance->m_containerEntity.get());
             }
@@ -219,11 +219,10 @@ namespace AzToolsFramework
                 entitiesInInstance.emplace_back(entity.get());
             }
 
-            InstanceEntityScrubber** instanceEntityScrubber = jsonDeserializerContext.GetMetadata().Find<InstanceEntityScrubber*>();
-            if (instanceEntityScrubber && (*instanceEntityScrubber))
-
+            InstanceEntityScrubber* instanceEntityScrubber = jsonDeserializerContext.GetMetadata().Find<InstanceEntityScrubber>();
+            if (instanceEntityScrubber)
             {
-                (*instanceEntityScrubber)->AddEntitiesToScrub(entitiesInInstance);
+                instanceEntityScrubber->AddEntitiesToScrub(entitiesInInstance);
             }
         }
 

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/InstanceToTemplateInterface.h

@@ -43,14 +43,12 @@ namespace AzToolsFramework
                 const PrefabDom& modifiedState, const LinkId linkId) = 0;
 
             //! Updates the affected template for a given entityId using the providedPatch
-            virtual bool PatchEntityInTemplate(PrefabDomValue& providedPatch, const AZ::EntityId& entityId) = 0;
-
-            virtual bool PatchEntityInTemplate(PrefabDomValue& providedPatch, const EntityAlias& entityAlias, const TemplateId& templateId) = 0;
+            virtual bool PatchEntityInTemplate(PrefabDom& providedPatch, AZ::EntityId entityId) = 0;
 
             virtual void AppendEntityAliasToPatchPaths(PrefabDom& providedPatch, const AZ::EntityId& entityId) = 0;
 
             //! Updates the template links (updating instances) for the given templateId using the providedPatch
-            virtual void PatchTemplate(PrefabDomValue& providedPatch, const TemplateId& templateId) = 0;
+            virtual bool PatchTemplate(PrefabDomValue& providedPatch, TemplateId templateId) = 0;
 
             virtual void ApplyPatchesToInstance(const AZ::EntityId& entityId, PrefabDom& patches, const Instance& instanceToAddPatches) = 0;
 

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/InstanceToTemplatePropagator.cpp

@@ -107,7 +107,7 @@ namespace AzToolsFramework
             return result.GetProcessing() != AZ::JsonSerializationResult::Processing::Halted;
         }
 
-        bool InstanceToTemplatePropagator::PatchEntityInTemplate(PrefabDomValue& providedPatch, const AZ::EntityId& entityId)
+        bool InstanceToTemplatePropagator::PatchEntityInTemplate(PrefabDom& providedPatch, AZ::EntityId entityId)
         {
             InstanceOptionalReference instanceOptionalReference = m_instanceEntityMapperInterface->FindOwningInstance(entityId);
 
@@ -119,54 +119,10 @@ namespace AzToolsFramework
                 return false;
             }
 
-            //get template space associated with instance
-            Instance& instance = instanceOptionalReference->get();
-            TemplateId templateId = instance.GetTemplateId();
-
-            //alias entity goes by in template -> get via owning instance map
-            AZStd::optional<EntityAlias> entityAlias = instance.GetEntityAlias(entityId);
-
-            if (!entityAlias)
-            {
-                AZ_Error("Prefab", false, "Failed to find an entity alias for the provided entity");
-                return false;
-            }
-
-            PrefabDom& templateDomReference = m_prefabSystemComponentInterface->FindTemplateDom(templateId);
-
-            return PatchEntityInTemplate(providedPatch, entityAlias.value(), templateId);
-        }
-
-        bool InstanceToTemplatePropagator::PatchEntityInTemplate(PrefabDomValue& providedPatch, const EntityAlias& entityAlias, const TemplateId& templateId)
-        {
-            PrefabDom& templateDomReference = m_prefabSystemComponentInterface->FindTemplateDom(templateId);
-
-            //query into the template dom for the alias
-            PrefabDomValueReference entityList = PrefabDomUtils::FindPrefabDomValue(templateDomReference, PrefabDomUtils::EntitiesName);
-
-            if (!entityList)
-            {
-                AZ_Error("Prefab", false, "Cannot patch entity in Template with id [%llu] because entity couldn't be found in the template", templateId);
-                return false;
-            }
-
-            PrefabDomValueReference entity = PrefabDomUtils::FindPrefabDomValue(entityList->get(), entityAlias.c_str());
-
-            if (!entity)
-            {
-                AZ_Error("Prefab", false, "Failed to aquire entity value reference");
-                return false;
-            }
-
-            //apply patch to section
-            AZ::JsonSerializationResult::ResultCode result = AZ::JsonSerialization::ApplyPatch(entity->get(),
-                templateDomReference.GetAllocator(), providedPatch, AZ::JsonMergeApproach::JsonPatch);
-
-            AZ_Error("Prefab", result.GetOutcome() == AZ::JsonSerializationResult::Outcomes::Success, "Patch was not successfully applied")
-
-            //trigger propagation
-            m_prefabSystemComponentInterface->PropagateTemplateChanges(templateId);
-            return true;
+            //get template id associated with instance
+            TemplateId templateId = instanceOptionalReference->get().GetTemplateId();
+            AppendEntityAliasToPatchPaths(providedPatch, entityId);
+            return PatchTemplate(providedPatch, templateId);
         }
 
         void InstanceToTemplatePropagator::AppendEntityAliasToPatchPaths(PrefabDom& providedPatch, const AZ::EntityId& entityId)
@@ -216,7 +172,7 @@ namespace AzToolsFramework
             }
         }
 
-        void InstanceToTemplatePropagator::PatchTemplate(PrefabDomValue& providedPatch, const TemplateId& templateId)
+        bool InstanceToTemplatePropagator::PatchTemplate(PrefabDomValue& providedPatch, TemplateId templateId)
         {
             PrefabDom& templateDomReference = m_prefabSystemComponentInterface->FindTemplateDom(templateId);
 
@@ -224,14 +180,17 @@ namespace AzToolsFramework
             AZ::JsonSerializationResult::ResultCode result = AZ::JsonSerialization::ApplyPatch(templateDomReference,
                 templateDomReference.GetAllocator(), providedPatch, AZ::JsonMergeApproach::JsonPatch);
 
-            AZ_Error("Prefab", result.GetOutcome() == AZ::JsonSerializationResult::Outcomes::Success,
-                "Patch was not successfully applied");
-
             //trigger propagation
             if (result.GetOutcome() == AZ::JsonSerializationResult::Outcomes::Success)
             {
                 m_prefabSystemComponentInterface->SetTemplateDirtyFlag(templateId, true);
                 m_prefabSystemComponentInterface->PropagateTemplateChanges(templateId);
+                return true;
+            }
+            else
+            {
+                AZ_Error("Prefab", false, "Patch was not successfully applied");
+                return false;
             }
         }
 
@@ -288,6 +247,8 @@ namespace AzToolsFramework
 
             AddPatchesToLink(patches, linkToApplyPatches);
             linkToApplyPatches.UpdateTarget();
+
+            m_prefabSystemComponentInterface->SetTemplateDirtyFlag(linkToApplyPatches.GetTargetTemplateId(), true);
             m_prefabSystemComponentInterface->PropagateTemplateChanges(linkToApplyPatches.GetTargetTemplateId());
         }
 
@@ -314,7 +275,6 @@ namespace AzToolsFramework
             PrefabDom& linkDom = link.GetLinkDom();
             PrefabDomValueReference linkPatchesReference =
                 PrefabDomUtils::FindPrefabDomValue(linkDom, PrefabDomUtils::PatchesName);
-            PrefabDom& templateDomReference = m_prefabSystemComponentInterface->FindTemplateDom(link.GetTargetTemplateId());
 
             // This logic only covers addition of patches. If patches already exists, the given list of patches must be appended to them.
             if (!linkPatchesReference.has_value())

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/InstanceToTemplatePropagator.h

@@ -31,21 +31,19 @@ namespace AzToolsFramework
             bool GeneratePatch(PrefabDom& generatedPatch, const PrefabDom& initialState, const PrefabDom& modifiedState) override;
             bool GeneratePatchForLink(PrefabDom& generatedPatch, const PrefabDom& initialState,
                 const PrefabDom& modifiedState, LinkId linkId) override;
-            bool PatchEntityInTemplate(PrefabDomValue& providedPatch, const AZ::EntityId& entityId) override;
-            bool PatchEntityInTemplate(PrefabDomValue& providedPatch, const EntityAlias& entityAlias, const TemplateId& templateId) override;
+            bool PatchEntityInTemplate(PrefabDom& providedPatch, AZ::EntityId entityId) override;
 
             void AppendEntityAliasToPatchPaths(PrefabDom& providedPatch, const AZ::EntityId& entityId) override;
 
             InstanceOptionalReference GetTopMostInstanceInHierarchy(AZ::EntityId entityId);
 
-            void PatchTemplate(PrefabDomValue& providedPatch, const AzToolsFramework::Prefab::TemplateId& templateId) override;
+            bool PatchTemplate(PrefabDomValue& providedPatch, TemplateId templateId) override;
 
             void ApplyPatchesToInstance(const AZ::EntityId& entityId, PrefabDom& patches, const Instance& instanceToAddPatches) override;
 
             void AddPatchesToLink(PrefabDom& patches, Link& link);
 
         private:
-            
 
             InstanceEntityMapperInterface* m_instanceEntityMapperInterface;
             PrefabSystemComponentInterface* m_prefabSystemComponentInterface;

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/InstanceUpdateExecutor.cpp

@@ -15,10 +15,12 @@
 #include <AzCore/Component/TickBus.h>
 #include <AzCore/Interface/Interface.h>
 #include <AzToolsFramework/Entity/EditorEntityContextBus.h>
+#include <AzToolsFramework/Entity/EditorEntityHelpers.h>
 #include <AzToolsFramework/API/ToolsApplicationAPI.h>
 #include <AzToolsFramework/Prefab/Instance/Instance.h>
 #include <AzToolsFramework/Prefab/Instance/TemplateInstanceMapperInterface.h>
 #include <AzToolsFramework/Prefab/PrefabDomUtils.h>
+#include <AzToolsFramework/Prefab/PrefabPublicInterface.h>
 #include <AzToolsFramework/Prefab/PrefabSystemComponentInterface.h>
 #include <AzToolsFramework/Prefab/Template/Template.h>
 #include <AzToolsFramework/UI/Outliner/EntityOutlinerWidgetInterface.h>
@@ -115,14 +117,32 @@ namespace AzToolsFramework
                                     "Could not find Template using Id '%llu'. Unable to update Instance.",
                                     currentTemplateId);
 
+                                // Remove the instance from update queue if its corresponding template couldn't be found
                                 isUpdateSuccessful = false;
+                                m_instancesUpdateQueue.pop();
+                                continue;
                             }
                         }
 
+                        auto findInstancesResult = m_templateInstanceMapperInterface->FindInstancesOwnedByTemplate(instanceTemplateId)->get();
+
+                        if (findInstancesResult.find(instanceToUpdate) == findInstancesResult.end())
+                        {
+                            // Since nested instances get reconstructed during propagation, remove any nested instance that no longer
+                            // maps to a template.
+                            isUpdateSuccessful = false;
+                            m_instancesUpdateQueue.pop();
+                            continue;
+                        }
+
                         Template& currentTemplate = currentTemplateReference->get();
                         Instance::EntityList newEntities;
-                        if (!PrefabDomUtils::LoadInstanceFromPrefabDom(
-                                *instanceToUpdate, newEntities, currentTemplate.GetPrefabDom()))
+                        if (PrefabDomUtils::LoadInstanceFromPrefabDom(*instanceToUpdate, newEntities, currentTemplate.GetPrefabDom()))
+                        {
+                            AzToolsFramework::EditorEntityContextRequestBus::Broadcast(
+                                &AzToolsFramework::EditorEntityContextRequests::HandleEntitiesAdded, newEntities);
+                        }
+                        else
                         {
                             AZ_Error(
                                 "Prefab", false,
@@ -132,22 +152,34 @@ namespace AzToolsFramework
 
                             isUpdateSuccessful = false;
                         }
-                        AzToolsFramework::EditorEntityContextRequestBus::Broadcast(
-                            &AzToolsFramework::EditorEntityContextRequests::HandleEntitiesAdded, newEntities);
 
                         m_instancesUpdateQueue.pop();
-
                     }
 
+                    for (auto entityIdIterator = selectedEntityIds.begin(); entityIdIterator != selectedEntityIds.end(); entityIdIterator++)
+                    {
+                        // Since entities get recreated during propagation, we need to check whether the entities correspoding to the list
+                        // of selected entity ids are present or not.
+                        AZ::Entity* entity = GetEntityById(*entityIdIterator);
+                        if (entity == nullptr)
+                        {
+                            selectedEntityIds.erase(entityIdIterator--);
+                        }
+                    }
                     ToolsApplicationRequestBus::Broadcast(&ToolsApplicationRequests::SetSelectedEntities, selectedEntityIds);
 
                     // Enable the Outliner
-                    AZ::SystemTickBus::QueueFunction([entityOutlinerWidgetInterface]() {
-                        if (entityOutlinerWidgetInterface)
+                    if (entityOutlinerWidgetInterface)
+                    {
+                        entityOutlinerWidgetInterface->SetUpdatesEnabled(true);
+
+                        auto prefabPublicInterface = AZ::Interface<PrefabPublicInterface>::Get();
+                        if (prefabPublicInterface)
                         {
-                            entityOutlinerWidgetInterface->SetUpdatesEnabled(true);
+                            AZ::EntityId rootEntityId = prefabPublicInterface->GetLevelInstanceContainerEntityId();
+                            entityOutlinerWidgetInterface->ExpandEntityChildren(rootEntityId);
                         }
-                    });
+                    }
                 }
 
                 m_updatingTemplateInstancesInQueue = false;

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabDomUtils.cpp

@@ -10,6 +10,7 @@
 *
 */
 
+#include <AzCore/Asset/AssetManager.h>
 #include <AzCore/JSON/prettywriter.h>
 #include <AzCore/Serialization/Json/JsonSerialization.h>
 #include <AzToolsFramework/Entity/EditorEntityContextBus.h>
@@ -78,6 +79,11 @@ namespace AzToolsFramework
 
             bool LoadInstanceFromPrefabDom(Instance& instance, const PrefabDom& prefabDom, LoadInstanceFlags flags)
             {
+                // When entities are rebuilt they are first destroyed. As a result any assets they were exclusively holding on to will
+                // be released and reloaded once the entities are built up again. By suspending asset release temporarily the asset reload
+                // is avoided.
+                AZ::Data::AssetManager::Instance().SuspendAssetRelease();
+
                 InstanceEntityIdMapper entityIdMapper;
                 entityIdMapper.SetLoadingInstance(instance);
                 if ((flags & LoadInstanceFlags::AssignRandomEntityId) == LoadInstanceFlags::AssignRandomEntityId)
@@ -91,10 +97,12 @@ namespace AzToolsFramework
                 // data has strict typing and doesn't look for inheritance both have to be explicitly added so they're found both locations.
                 settings.m_metadata.Add(static_cast<AZ::JsonEntityIdSerializer::JsonEntityIdMapper*>(&entityIdMapper));
                 settings.m_metadata.Add(&entityIdMapper);
-
+                
                 AZ::JsonSerializationResult::ResultCode result =
                     AZ::JsonSerialization::Load(instance, prefabDom, settings);
 
+                AZ::Data::AssetManager::Instance().ResumeAssetRelease();
+
                 if (result.GetProcessing() == AZ::JsonSerializationResult::Processing::Halted)
                 {
                     AZ_Error("Prefab", false,
@@ -110,6 +118,11 @@ namespace AzToolsFramework
             bool LoadInstanceFromPrefabDom(
                 Instance& instance, Instance::EntityList& newlyAddedEntities, const PrefabDom& prefabDom, LoadInstanceFlags flags)
             {
+                // When entities are rebuilt they are first destroyed. As a result any assets they were exclusively holding on to will
+                // be released and reloaded once the entities are built up again. By suspending asset release temporarily the asset reload
+                // is avoided.
+                AZ::Data::AssetManager::Instance().SuspendAssetRelease();
+
                 InstanceEntityIdMapper entityIdMapper;
                 entityIdMapper.SetLoadingInstance(instance);
                 if ((flags & LoadInstanceFlags::AssignRandomEntityId) == LoadInstanceFlags::AssignRandomEntityId)
@@ -123,16 +136,16 @@ namespace AzToolsFramework
                 // data has strict typing and doesn't look for inheritance both have to be explicitly added so they're found both locations.
                 settings.m_metadata.Add(static_cast<AZ::JsonEntityIdSerializer::JsonEntityIdMapper*>(&entityIdMapper));
                 settings.m_metadata.Add(&entityIdMapper);
+                settings.m_metadata.Create<InstanceEntityScrubber>(newlyAddedEntities);
 
-                InstanceEntityScrubber instanceEntityScrubber(newlyAddedEntities);
-                settings.m_metadata.Add(&instanceEntityScrubber);
+                AZ::JsonSerializationResult::ResultCode result = AZ::JsonSerialization::Load(instance, prefabDom, settings);
 
-                AZ::JsonSerializationResult::ResultCode result =
-                    AZ::JsonSerialization::Load(instance, prefabDom, settings);
+                AZ::Data::AssetManager::Instance().ResumeAssetRelease();
 
                 if (result.GetProcessing() == AZ::JsonSerializationResult::Processing::Halted)
                 {
-                    AZ_Error("Prefab", false,
+                    AZ_Error(
+                        "Prefab", false,
                         "Failed to de-serialize Prefab Instance from Prefab DOM. "
                         "Unable to proceed.");
 

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabLoader.cpp

@@ -39,7 +39,7 @@ namespace AzToolsFramework
             auto settingsRegistry = AZ::SettingsRegistry::Get();
             AZ_Assert(settingsRegistry, "Settings registry is not set");
             
-            bool result =
+            [[maybe_unused]] bool result =
                 settingsRegistry->Get(m_projectPathWithOsSeparator.Native(), AZ::SettingsRegistryMergeUtils::FilePathKey_ProjectPath);
             AZ_Assert(result, "Couldn't retrieve project root path");
             m_projectPathWithSlashSeparator = AZ::IO::Path(m_projectPathWithOsSeparator.Native(), '/').MakePreferred();
@@ -182,7 +182,6 @@ namespace AzToolsFramework
                 for (PrefabDomValue::MemberIterator instanceIterator = instances.MemberBegin(); instanceIterator != instances.MemberEnd();
                      ++instanceIterator)
                 {
-                    const PrefabDomValue& instance = instanceIterator->value;
                     if (!LoadNestedInstance(instanceIterator, newTemplateId, progressedFilePathsSet))
                     {
                         isLoadedWithErrors = true;
@@ -349,8 +348,7 @@ namespace AzToolsFramework
                     "Prefab", false,
                     "PrefabLoader::SaveTemplate - Unable to save Prefab Template with id: %llu. "
                     "Template with that id is invalid",
-                    templateId
-                );
+                    templateId);
 
                 return AZStd::nullopt;
             }

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.cpp

@@ -15,18 +15,20 @@
 #include <AzCore/Component/TransformBus.h>
 #include <AzCore/Utils/TypeHash.h>
 
+#include <AzToolsFramework/API/ToolsApplicationAPI.h>
 #include <AzToolsFramework/Entity/EditorEntityContextBus.h>
 #include <AzToolsFramework/Entity/EditorEntityHelpers.h>
 #include <AzToolsFramework/Entity/EditorEntityInfoBus.h>
 #include <AzToolsFramework/Entity/PrefabEditorEntityOwnershipInterface.h>
-#include <AzToolsFramework/Prefab/EditorPrefabComponent.h>
 #include <AzToolsFramework/Prefab/Instance/Instance.h>
 #include <AzToolsFramework/Prefab/Instance/InstanceEntityIdMapper.h>
 #include <AzToolsFramework/Prefab/Instance/InstanceEntityMapperInterface.h>
 #include <AzToolsFramework/Prefab/Instance/InstanceToTemplateInterface.h>
+#include <AzToolsFramework/Prefab/PrefabDomUtils.h>
 #include <AzToolsFramework/Prefab/PrefabLoaderInterface.h>
 #include <AzToolsFramework/Prefab/PrefabSystemComponentInterface.h>
 #include <AzToolsFramework/Prefab/PrefabUndo.h>
+#include <AzToolsFramework/Prefab/PrefabUndoHelpers.h>
 #include <AzToolsFramework/ToolsComponents/TransformComponent.h>
 
 namespace AzToolsFramework
@@ -36,12 +38,14 @@ namespace AzToolsFramework
         void PrefabPublicHandler::RegisterPrefabPublicHandlerInterface()
         {
             m_instanceEntityMapperInterface = AZ::Interface<InstanceEntityMapperInterface>::Get();
-            AZ_Assert(
-                m_instanceEntityMapperInterface, "PrefabPublicHandler - Could not retrieve instance of InstanceEntityMapperInterface");
+            AZ_Assert(m_instanceEntityMapperInterface, "PrefabPublicHandler - Could not retrieve instance of InstanceEntityMapperInterface");
 
             m_instanceToTemplateInterface = AZ::Interface<InstanceToTemplateInterface>::Get();
             AZ_Assert(m_instanceToTemplateInterface, "PrefabPublicHandler - Could not retrieve instance of InstanceToTemplateInterface");
 
+            m_prefabLoaderInterface = AZ::Interface<PrefabLoaderInterface>::Get();
+            AZ_Assert(m_prefabLoaderInterface, "Could not get PrefabLoaderInterface on PrefabPublicHandler construction.");
+
             m_prefabSystemComponentInterface = AZ::Interface<PrefabSystemComponentInterface>::Get();
             AZ_Assert(m_prefabSystemComponentInterface, "Could not get PrefabSystemComponentInterface on PrefabPublicHandler construction.");
 
@@ -57,93 +61,161 @@ namespace AzToolsFramework
             m_prefabUndoCache.Destroy();
         }
 
-        PrefabOperationResult PrefabPublicHandler::CreatePrefab(const AZStd::vector<AZ::EntityId>& entityIds, AZStd::string_view filePath)
+        PrefabOperationResult PrefabPublicHandler::CreatePrefab(const AZStd::vector<AZ::EntityId>& entityIds, AZ::IO::PathView filePath)
+        {
+            EntityList inputEntityList, topLevelEntities;
+            AZ::EntityId commonRootEntityId;
+            InstanceOptionalReference commonRootEntityOwningInstance;
+            PrefabOperationResult findCommonRootOutcome = FindCommonRootOwningInstance(
+                entityIds, inputEntityList, topLevelEntities, commonRootEntityId, commonRootEntityOwningInstance);
+            if (!findCommonRootOutcome.IsSuccess())
+            {
+                return findCommonRootOutcome;
+            }
+
+            InstanceOptionalReference instanceToCreate;
+            {
+                // Initialize Undo Batch object
+                ScopedUndoBatch undoBatch("Create Prefab");
+
+                PrefabDom commonRootInstanceDomBeforeCreate;
+                m_instanceToTemplateInterface->GenerateDomForInstance(
+                    commonRootInstanceDomBeforeCreate, commonRootEntityOwningInstance->get());
+
+                AZStd::vector<AZ::Entity*> entities;
+                AZStd::vector<AZStd::unique_ptr<Instance>> instances;
+
+                // Retrieve all entities affected and identify Instances
+                if (!RetrieveAndSortPrefabEntitiesAndInstances(inputEntityList, commonRootEntityOwningInstance->get(), entities, instances))
+                {
+                    return AZ::Failure(
+                        AZStd::string("Could not create a new prefab out of the entities provided - entities do not share a common root."));
+                }
+
+                // When we create a prefab with other prefab instances, we have to remove the existing links between the source and 
+                // target templates of the other instances.
+                for (auto& nestedInstance : instances)
+                {
+                    PrefabUndoHelpers::RemoveLink(
+                        nestedInstance->GetTemplateId(), commonRootEntityOwningInstance->get().GetTemplateId(),
+                        nestedInstance->GetInstanceAlias(), nestedInstance->GetLinkId(), undoBatch.GetUndoBatch());
+                }
+
+                auto prefabEditorEntityOwnershipInterface = AZ::Interface<PrefabEditorEntityOwnershipInterface>::Get();
+                if (!prefabEditorEntityOwnershipInterface)
+                {
+                    return AZ::Failure(AZStd::string("Could not create a new prefab out of the entities provided - internal error "
+                                                     "(PrefabEditorEntityOwnershipInterface unavailable)."));
+                }
+
+                // Create the Prefab
+                instanceToCreate = prefabEditorEntityOwnershipInterface->CreatePrefab(
+                    entities, AZStd::move(instances), filePath, commonRootEntityOwningInstance);
+
+                if (!instanceToCreate)
+                {
+                    return AZ::Failure(AZStd::string("Could not create a new prefab out of the entities provided - internal error "
+                                                     "(A null instance is returned)."));
+                }
+
+                PrefabUndoHelpers::UpdatePrefabInstance(
+                    commonRootEntityOwningInstance->get(), "Update prefab instance", commonRootInstanceDomBeforeCreate, undoBatch.GetUndoBatch());
+
+                CreateLink(
+                    topLevelEntities, instanceToCreate->get(), commonRootEntityOwningInstance->get().GetTemplateId(), undoBatch.GetUndoBatch(),
+                    commonRootEntityId);
+                AZ::EntityId containerEntityId = instanceToCreate->get().GetContainerEntityId();
+
+                // Change top level entities to be parented to the container entity
+                // Mark them as dirty so this change is correctly applied to the template
+                for (AZ::Entity* topLevelEntity : topLevelEntities)
+                {
+                    m_prefabUndoCache.UpdateCache(topLevelEntity->GetId());
+                    undoBatch.MarkEntityDirty(topLevelEntity->GetId());
+                    AZ::TransformBus::Event(topLevelEntity->GetId(), &AZ::TransformBus::Events::SetParent, containerEntityId);
+                }
+                
+                // Select Container Entity
+                {
+                    auto selectionUndo = aznew SelectionCommand({containerEntityId}, "Select Prefab Container Entity");
+                    selectionUndo->SetParent(undoBatch.GetUndoBatch());
+                    ToolsApplicationRequestBus::Broadcast(&ToolsApplicationRequestBus::Events::RunRedoSeparately, selectionUndo);
+                }
+            }
+
+            // Save Template to file
+            m_prefabLoaderInterface->SaveTemplate(instanceToCreate->get().GetTemplateId());
+            
+            return AZ::Success();
+        }
+
+        PrefabOperationResult PrefabPublicHandler::FindCommonRootOwningInstance(
+            const AZStd::vector<AZ::EntityId>& entityIds, EntityList& inputEntityList, EntityList& topLevelEntities,
+            AZ::EntityId& commonRootEntityId, InstanceOptionalReference& commonRootEntityOwningInstance)
         {
             // Retrieve entityList from entityIds
-            EntityList inputEntityList;
-            EntityIdListToEntityList(entityIds, inputEntityList);
+            inputEntityList = EntityIdListToEntityList(entityIds);
 
             // Find common root and top level entities
             bool entitiesHaveCommonRoot = false;
-            AZ::EntityId commonRootEntityId;
-            EntityList topLevelEntities;
 
             AzToolsFramework::ToolsApplicationRequests::Bus::BroadcastResult(
-                entitiesHaveCommonRoot,
-                &AzToolsFramework::ToolsApplicationRequests::FindCommonRootInactive,
-                inputEntityList,
-                commonRootEntityId,
-                &topLevelEntities
-            );
+                entitiesHaveCommonRoot, &AzToolsFramework::ToolsApplicationRequests::FindCommonRootInactive, inputEntityList,
+                commonRootEntityId, &topLevelEntities);
 
             // Bail if entities don't share a common root
             if (!entitiesHaveCommonRoot)
             {
-                return AZ::Failure(AZStd::string("Could not create a new prefab out of the entities provided - entities do not share a common root."));
-            }
-
-            AZ::Entity* commonRootEntity = nullptr;
-            if (commonRootEntityId.IsValid())
-            {
-                commonRootEntity = GetEntityById(commonRootEntityId);
+                return AZ::Failure(AZStd::string("Failed to create a prefab: Provided entities do not share a common root."));
             }
 
             // Retrieve the owning instance of the common root entity, which will be our new instance's parent instance.
-            InstanceOptionalReference commonRootEntityOwningInstance = GetOwnerInstanceByEntityId(commonRootEntityId);
-            AZ_Assert(commonRootEntityOwningInstance.has_value(), "Failed to create prefab : "
-                "Couldn't get a valid owning instance for the common root entity of the enities provided");
-
-            AZStd::vector<AZ::Entity*> entities;
-            AZStd::vector<AZStd::unique_ptr<Instance>> instances;
-
-            // Retrieve all entities affected and identify Instances
-            if (!RetrieveAndSortPrefabEntitiesAndInstances(inputEntityList, commonRootEntityOwningInstance->get(), entities, instances))
+            commonRootEntityOwningInstance = GetOwnerInstanceByEntityId(commonRootEntityId);
+            if (!commonRootEntityOwningInstance)
             {
-                return AZ::Failure(AZStd::string("Could not create a new prefab out of the entities provided - entities do not share a common root."));
+                AZ_Assert(
+                    false,
+                    "Failed to create prefab : Couldn't get a valid owning instance for the common root entity of the enities provided");
+                return AZ::Failure(AZStd::string(
+                    "Failed to create prefab : Couldn't get a valid owning instance for the common root entity of the enities provided"));
             }
+            return AZ::Success();
+        }
 
-            auto prefabEditorEntityOwnershipInterface = AZ::Interface<PrefabEditorEntityOwnershipInterface>::Get();
-            if (!prefabEditorEntityOwnershipInterface)
-            {
-                return AZ::Failure(AZStd::string("Could not create a new prefab out of the entities provided - internal error "
-                                                 "(PrefabEditorEntityOwnershipInterface unavailable)."));
-            }
+        void PrefabPublicHandler::CreateLink(
+            const EntityList& topLevelEntities, Instance& sourceInstance, TemplateId targetTemplateId,
+            UndoSystem::URSequencePoint* undoBatch, AZ::EntityId commonRootEntityId)
+        {
+            AZ::EntityId containerEntityId = sourceInstance.GetContainerEntityId();
+            AZ::Entity* containerEntity = GetEntityById(containerEntityId);
+            Prefab::PrefabDom containerEntityDomBefore;
+            m_instanceToTemplateInterface->GenerateDomForEntity(containerEntityDomBefore, *containerEntity);
 
-            InstanceOptionalReference instance = prefabEditorEntityOwnershipInterface->CreatePrefab(
-                entities, AZStd::move(instances), filePath, commonRootEntityOwningInstance);
-
-            if (!instance)
-            {
-                return AZ::Failure(AZStd::string("Could not create a new prefab out of the entities provided - internal error "
-                                                 "(A null instance is returned)."));
-            }
-
-            AZ::EntityId containerEntityId = instance->get().GetContainerEntityId();
             AZ::Vector3 containerEntityTranslation(AZ::Vector3::CreateZero());
             AZ::Quaternion containerEntityRotation(AZ::Quaternion::CreateZero());
 
             // Set the transform (translation, rotation) of the container entity
             GenerateContainerEntityTransform(topLevelEntities, containerEntityTranslation, containerEntityRotation);
 
+            // Set container entity to be child of common root
+            AZ::TransformBus::Event(containerEntityId, &AZ::TransformBus::Events::SetParent, commonRootEntityId);
+
             AZ::TransformBus::Event(containerEntityId, &AZ::TransformBus::Events::SetLocalTranslation, containerEntityTranslation);
             AZ::TransformBus::Event(containerEntityId, &AZ::TransformBus::Events::SetLocalRotationQuaternion, containerEntityRotation);
 
-            // Set container entity to be child of common root
-            AZ::TransformBus::Event(containerEntityId, &AZ::TransformBus::Events::SetParent, commonRootEntityId);
-            
-            // Assign the EditorPrefabComponent to the instance container
-            EntityCompositionRequests::AddComponentsOutcome outcome;
-            EntityCompositionRequestBus::BroadcastResult(
-                outcome, &EntityCompositionRequests::AddComponentsToEntities, EntityIdList{containerEntityId},
-                AZ::ComponentTypeList{azrtti_typeid<AzToolsFramework::Prefab::EditorPrefabComponent>()});
-            
-            // Change top level entities to be parented to the container entity
-            for (AZ::Entity* topLevelEntity : topLevelEntities)
-            {
-                AZ::TransformBus::Event(topLevelEntity->GetId(), &AZ::TransformBus::Events::SetParent, containerEntityId);
-            }
-            
-            return AZ::Success();
+            PrefabDom containerEntityDomAfter;
+            m_instanceToTemplateInterface->GenerateDomForEntity(containerEntityDomAfter, *containerEntity);
+
+            PrefabDom patch;
+            m_instanceToTemplateInterface->GeneratePatch(patch, containerEntityDomBefore, containerEntityDomAfter);
+            m_instanceToTemplateInterface->AppendEntityAliasToPatchPaths(patch, containerEntityId);
+
+            PrefabUndoHelpers::CreateLink(
+                sourceInstance.GetTemplateId(), targetTemplateId, patch, sourceInstance.GetInstanceAlias(),
+                undoBatch);
+
+            // Update the cache - this prevents these changes from being stored in the regular undo/redo nodes
+            m_prefabUndoCache.Store(containerEntityId, AZStd::move(containerEntityDomAfter));
         }
 
         PrefabOperationResult PrefabPublicHandler::InstantiatePrefab(AZStd::string_view /*filePath*/, AZ::EntityId /*parent*/, AZ::Vector3 /*position*/)
@@ -173,14 +245,7 @@ namespace AzToolsFramework
                     AZStd::string("SavePrefab - Path error. Path could be invalid, or the prefab may not be loaded in this level."));
             }
 
-            auto prefabLoaderInterface = AZ::Interface<PrefabLoaderInterface>::Get();
-            if (prefabLoaderInterface == nullptr)
-            {
-                return AZ::Failure(AZStd::string(
-                    "Could not save prefab - internal error (PrefabLoaderInterface unavailable)."));
-            }
-
-            if (!prefabLoaderInterface->SaveTemplate(templateId))
+            if (!m_prefabLoaderInterface->SaveTemplate(templateId))
             {
                 return AZ::Failure(AZStd::string("Could not save prefab - internal error (Json write operation failure)."));
             }
@@ -247,23 +312,8 @@ namespace AzToolsFramework
 
             ToolsApplicationRequests::Bus::Broadcast(&ToolsApplicationRequests::SetSelectedEntities, selection);
 
-            PrefabDom instanceDomAfterUpdate;
-            m_instanceToTemplateInterface->GenerateDomForInstance(instanceDomAfterUpdate, entityOwningInstance);
-
-            // Generate the patch comparing the instance before and after the entity addition.
-            PrefabDom patch;
-            if (!m_instanceToTemplateInterface->GeneratePatch(patch, instanceDomBeforeUpdate, instanceDomAfterUpdate))
-            {
-                return AZ::Failure(AZStd::string::format(
-                    "A valid patch couldn't be created for adding an entity with id '%llu'", static_cast<AZ::u64>(entityId)));
-            }
-
-            // create undo node
-            PrefabUndoInstance* state = aznew PrefabUndoInstance(AZStd::string::format("%llu", static_cast<AZ::u64>(entityId)));
-            state->Capture(instanceDomBeforeUpdate, instanceDomAfterUpdate, entityOwningInstance.GetTemplateId());
-            state->SetParent(undoBatch.GetUndoBatch());
-
-            state->Redo();
+            PrefabUndoHelpers::UpdatePrefabInstance(
+                entityOwningInstance, "Undo adding entity", instanceDomBeforeUpdate, undoBatch.GetUndoBatch());
 
             return AZ::Success(entityId);
         }
@@ -276,13 +326,13 @@ namespace AzToolsFramework
 
             if (instanceOptionalReference.has_value())
             {
-                PrefabDom beforeState;
-                m_prefabUndoCache.Retrieve(entityId, beforeState);
-
                 PrefabDom afterState;
                 AZ::Entity* entity = GetEntityById(entityId);
                 if (entity)
                 {
+                    PrefabDom beforeState;
+                    m_prefabUndoCache.Retrieve(entityId, beforeState);
+
                     m_instanceToTemplateInterface->GenerateDomForEntity(afterState, *entity);
 
                     PrefabDom patch;
@@ -301,7 +351,10 @@ namespace AzToolsFramework
                     // Update the cache
                     m_prefabUndoCache.Store(entityId, AZStd::move(afterState));
                 }
-                
+                else
+                {
+                    m_prefabUndoCache.PurgeCache(entityId);
+                }
             }
         }
 
@@ -433,8 +486,7 @@ namespace AzToolsFramework
             InstanceOptionalReference instance = GetOwnerInstanceByEntityId(entityIds[0]);
 
             // Retrieve entityList from entityIds
-            EntityList inputEntityList;
-            EntityIdListToEntityList(entityIds, inputEntityList);
+            EntityList inputEntityList = EntityIdListToEntityList(entityIds);
 
             AZ_PROFILE_FUNCTION(AZ::Debug::ProfileCategory::AzToolsFramework);
 
@@ -643,14 +695,17 @@ namespace AzToolsFramework
         }
 
         bool PrefabPublicHandler::RetrieveAndSortPrefabEntitiesAndInstances(
-            const EntityList& inputEntities, const Instance& commonRootEntityOwningInstance,
+            const EntityList& inputEntities, Instance& commonRootEntityOwningInstance,
             EntityList& outEntities, AZStd::vector<AZStd::unique_ptr<Instance>>& outInstances) const
         {
             AZStd::queue<AZ::Entity*> entityQueue;
 
             for (auto inputEntity : inputEntities)
             {
-                entityQueue.push(inputEntity);
+                if (inputEntity && !IsLevelInstanceContainerEntity(inputEntity->GetId()))
+                {
+                    entityQueue.push(inputEntity);
+                }
             }
 
             // Support sets to easily identify if we're processing the same entity multiple times.
@@ -664,17 +719,19 @@ namespace AzToolsFramework
 
                 // Get this entity's owning instance.
                 InstanceOptionalReference owningInstance = m_instanceEntityMapperInterface->FindOwningInstance(entity->GetId());
-                AZ_Assert(owningInstance.has_value(), "An error occored while retrieving entities and prefab instances : "
-                    "Owning instance of entity with id '%llu' couldn't be found", entity->GetId());
+                AZ_Assert(
+                    owningInstance.has_value(),
+                    "An error occurred while retrieving entities and prefab instances : "
+                    "Owning instance of entity with id '%llu' couldn't be found",
+                    entity->GetId());
 
                 // Check if this entity is owned by the same instance owning the root.
                 if (&owningInstance->get() == &commonRootEntityOwningInstance)
                 {
-                    AZStd::unique_ptr<AZ::Entity> detachedEntity = owningInstance->get().DetachEntity(entity->GetId());
                     // If it's the same instance, we can add this entity to the new instance entities.
                     int priorEntitiesSize = entities.size();
                     
-                    entities.insert(detachedEntity.release());
+                    entities.insert(entity);
 
                     // If the size of entities increased, then it wasn't added before.
                     // In that case, add the children of this entity to the queue.
@@ -714,20 +771,18 @@ namespace AzToolsFramework
 
             // Store results
             outEntities.clear();
-            outEntities.resize(entities.size());
-            AZStd::copy(entities.begin(), entities.end(), outEntities.begin());
+            outEntities.reserve(entities.size());
+
+            for (AZ::Entity* entity : entities)
+            {
+                outEntities.emplace_back(commonRootEntityOwningInstance.DetachEntity(entity->GetId()).release());
+            }
 
             outInstances.clear();
             outInstances.reserve(instances.size());
             for (Instance* instancePtr : instances)
             {
-                auto parentInstance = instancePtr->GetParentInstance();
-
-                if (parentInstance.has_value())
-                {
-                    auto uniquePtr = parentInstance->get().DetachNestedInstance(instancePtr->GetInstanceAlias());
-                    outInstances.push_back(AZStd::move(uniquePtr));
-                }
+                outInstances.push_back(AZStd::move(commonRootEntityOwningInstance.DetachNestedInstance(instancePtr->GetInstanceAlias())));
             }
 
             return true;
@@ -745,8 +800,20 @@ namespace AzToolsFramework
             for (AZ::EntityId entityId : entityIds)
             {
                 InstanceOptionalReference owningInstance = m_instanceEntityMapperInterface->FindOwningInstance(entityId);
-                // If this is the container entity, it actually represents the instance so get its owner
-                if (owningInstance->get().GetContainerEntityId() == entityId)
+
+                if (!owningInstance.has_value())
+                {
+                    AZ_Assert(
+                        false,
+                        "An error occurred in function EntitiesBelongToSameInstance: "
+                        "Owning instance of entity with id '%llu' couldn't be found",
+                        entityId);
+                    return false;
+                }
+
+                // If this is a container entity, it actually represents a child instance so get its owner.
+                // The only exception in the level root instance. We leave it as is to streamline operations.
+                if (owningInstance->get().GetContainerEntityId() == entityId && !IsLevelInstanceContainerEntity(entityId))
                 {
                     owningInstance = owningInstance->get().GetParentInstance();
                 }
@@ -766,18 +833,5 @@ namespace AzToolsFramework
 
             return true;
         }
-
-        void PrefabPublicHandler::EntityIdListToEntityList(const EntityIdList& inputEntityIds, EntityList& outEntities)
-        {
-            outEntities.reserve(inputEntityIds.size());
-
-            for (AZ::EntityId entityId : inputEntityIds)
-            {
-                if (entityId.IsValid())
-                {
-                    outEntities.emplace_back(GetEntityById(entityId));
-                }
-            }
-        }
     }
 }

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.h

@@ -27,8 +27,10 @@ namespace AzToolsFramework
     namespace Prefab
     {
         class Instance;
+
         class InstanceEntityMapperInterface;
         class InstanceToTemplateInterface;
+        class PrefabLoaderInterface;
         class PrefabSystemComponentInterface;
 
         class PrefabPublicHandler final
@@ -42,7 +44,7 @@ namespace AzToolsFramework
             void UnregisterPrefabPublicHandlerInterface();
 
             // PrefabPublicInterface...
-            PrefabOperationResult CreatePrefab(const AZStd::vector<AZ::EntityId>& entityIds, AZStd::string_view filePath) override;
+            PrefabOperationResult CreatePrefab(const AZStd::vector<AZ::EntityId>& entityIds, AZ::IO::PathView filePath) override;
             PrefabOperationResult InstantiatePrefab(AZStd::string_view filePath, AZ::EntityId parent, AZ::Vector3 position) override;
             PrefabOperationResult SavePrefab(AZ::IO::Path filePath) override;
             PrefabEntityResult CreateEntity(AZ::EntityId parentId, const AZ::Vector3& position) override;
@@ -61,19 +63,46 @@ namespace AzToolsFramework
 
         private:
             PrefabOperationResult DeleteFromInstance(const EntityIdList& entityIds, bool deleteDescendants);
-            bool RetrieveAndSortPrefabEntitiesAndInstances(const EntityList& inputEntities, const Instance& commonRootEntityOwningInstance,
+            bool RetrieveAndSortPrefabEntitiesAndInstances(const EntityList& inputEntities, Instance& commonRootEntityOwningInstance,
                 EntityList& outEntities, AZStd::vector<AZStd::unique_ptr<Instance>>& outInstances) const;
 
             InstanceOptionalReference GetOwnerInstanceByEntityId(AZ::EntityId entityId) const;
             bool EntitiesBelongToSameInstance(const EntityIdList& entityIds) const;
 
+            /**
+             * Creates a link between the templates of an instance and its parent.
+             * 
+             * \param topLevelEntities The list of entities that are immediate children to the container entity of the instance.
+             * \param sourceInstance The instance that corresponds to the source template of the link.
+             * \param targetInstance The id of the target template.
+             * \param undoBatch The undo batch to set as parent for this create link action.
+             * \param commonRootEntityId The id of the entity that the source instance should be parented under.
+             */
+            void CreateLink(
+                const EntityList& topLevelEntities, Instance& sourceInstance, TemplateId targetTemplateId,
+                UndoSystem::URSequencePoint* undoBatch, AZ::EntityId commonRootEntityId);
+
+            /**
+             * Given a list of entityIds, finds the prefab instance that owns the common root entity of the entityIds.
+             * 
+             * \param entityIds The list of entity ids.
+             * \param inputEntityList The list of entities corresponding to the entity ids.
+             * \param topLevelEntities The list of entities that are immediate children of the common root entity.
+             * \param commonRootEntityId The entity id of the common root entity of all the entityIds.
+             * \param commonRootEntityOwningInstance The owning instance of the common root entity.
+             * \return PrefabOperationResult indicating whether the action was successful or not.
+             */
+            PrefabOperationResult FindCommonRootOwningInstance(
+                const AZStd::vector<AZ::EntityId>& entityIds, EntityList& inputEntityList, EntityList& topLevelEntities,
+                AZ::EntityId& commonRootEntityId, InstanceOptionalReference& commonRootEntityOwningInstance);
+
             static Instance* GetParentInstance(Instance* instance);
             static Instance* GetAncestorOfInstanceThatIsChildOfRoot(const Instance* ancestor, Instance* descendant);
             static void GenerateContainerEntityTransform(const EntityList& topLevelEntities, AZ::Vector3& translation, AZ::Quaternion& rotation);
-            static void EntityIdListToEntityList(const EntityIdList& inputEntityIds, EntityList& outEntities);
 
             InstanceEntityMapperInterface* m_instanceEntityMapperInterface = nullptr;
             InstanceToTemplateInterface* m_instanceToTemplateInterface = nullptr;
+            PrefabLoaderInterface* m_prefabLoaderInterface = nullptr;
             PrefabSystemComponentInterface* m_prefabSystemComponentInterface = nullptr;
 
             // Caches entity states for undo/redo purposes

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicInterface.h

@@ -49,7 +49,7 @@ namespace AzToolsFramework
              * @param filePath The path for the new prefab file.
              * @return An outcome object; on failure, it comes with an error message detailing the cause of the error.
              */
-            virtual PrefabOperationResult CreatePrefab(const AZStd::vector<AZ::EntityId>& entityIds, AZStd::string_view filePath) = 0;
+            virtual PrefabOperationResult CreatePrefab(const AZStd::vector<AZ::EntityId>& entityIds, AZ::IO::PathView filePath) = 0;
 
             /**
              * Instantiate a prefab from a prefab file.

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.cpp

@@ -104,7 +104,6 @@ namespace AzToolsFramework
                 return nullptr;
             }
 
-             
             AZStd::unique_ptr<Instance> newInstance = AZStd::make_unique<Instance>(AZStd::move(containerEntity));
 
             for (AZ::Entity* entity : entities)
@@ -122,6 +121,7 @@ namespace AzToolsFramework
             }
 
             newInstance->SetTemplateSourcePath(relativeFilePath);
+            newInstance->SetContainerEntityName(relativeFilePath.Stem().Native());
 
             TemplateId newTemplateId = CreateTemplateFromInstance(*newInstance);
             if (newTemplateId == InvalidTemplateId)
@@ -142,7 +142,6 @@ namespace AzToolsFramework
 
         void PrefabSystemComponent::PropagateTemplateChanges(TemplateId templateId)
         {
-            UpdatePrefabInstances(templateId);
             auto templateIdToLinkIdsIterator = m_templateToLinkIdsMap.find(templateId);
             if (templateIdToLinkIdsIterator != m_templateToLinkIdsMap.end())
             {
@@ -153,15 +152,24 @@ namespace AzToolsFramework
                     templateIdToLinkIdsIterator->second.end()));
                 UpdateLinkedInstances(linkIdsToUpdateQueue);
             }
+            else
+            {
+                UpdatePrefabInstances(templateId);
+            }
         }
 
         void PrefabSystemComponent::UpdatePrefabTemplate(TemplateId templateId, const PrefabDom& updatedDom)
         {
-            PrefabDom& templateDomToUpdate = FindTemplateDom(templateId);
-            if (AZ::JsonSerialization::Compare(templateDomToUpdate, updatedDom) != AZ::JsonSerializerCompareResult::Equal)
+            auto templateToUpdate = FindTemplate(templateId);
+            if (templateToUpdate)
             {
-                templateDomToUpdate.CopyFrom(updatedDom, templateDomToUpdate.GetAllocator());
-                PropagateTemplateChanges(templateId);
+                PrefabDom& templateDomToUpdate = templateToUpdate->get().GetPrefabDom();
+                if (AZ::JsonSerialization::Compare(templateDomToUpdate, updatedDom) != AZ::JsonSerializerCompareResult::Equal)
+                {
+                    templateDomToUpdate.CopyFrom(updatedDom, templateDomToUpdate.GetAllocator());
+                    templateToUpdate->get().MarkAsDirty(true);
+                    PropagateTemplateChanges(templateId);
+                }
             }
         }
 
@@ -498,12 +506,14 @@ namespace AzToolsFramework
                 return false;
             }
 
-            Template& sourceTemplate = sourceTemplateReference->get();
             Template& targetTemplate = targetTemplateReference->get();
 
+#if defined(AZ_ENABLE_TRACING)
+            Template& sourceTemplate = sourceTemplateReference->get();
             AZStd::string_view instanceName(instanceIterator->name.GetString(), instanceIterator->name.GetStringLength());
             const AZStd::string& targetTemplateFilePath = targetTemplate.GetFilePath().Native();
             const AZStd::string& sourceTemplateFilePath = sourceTemplate.GetFilePath().Native();
+#endif
 
             LinkId newLinkId = CreateUniqueLinkId();
             Link newLink(newLinkId);
@@ -613,7 +623,12 @@ namespace AzToolsFramework
                 instancesValue = memberFound->value;
             }
 
-            instancesValue->get().AddMember(rapidjson::StringRef(instanceAlias.c_str()), PrefabDomValue(), targetTemplateDom.GetAllocator());
+            // Only add the instance if it's not there already
+            if (instancesValue->get().FindMember(rapidjson::StringRef(instanceAlias.c_str())) == instancesValue->get().MemberEnd())
+            {
+                instancesValue->get().AddMember(
+                    rapidjson::StringRef(instanceAlias.c_str()), PrefabDomValue(), targetTemplateDom.GetAllocator());
+            }
 
             Template& sourceTemplate = sourceTemplateRef->get();
 
@@ -731,10 +746,11 @@ namespace AzToolsFramework
             }
 
             Template& sourceTemplate = sourceTemplateReference->get();
+#if defined(AZ_ENABLE_TRACING)
             Template& targetTemplate = targetTemplateReference->get();
+#endif
 
             AZStd::string_view instanceName(instanceIterator->name.GetString(), instanceIterator->name.GetStringLength());
-            const AZStd::string& targetTemplateFilePath = targetTemplate.GetFilePath().Native();
 
             link.SetSourceTemplateId(sourceTemplateId);
             link.SetTargetTemplateId(targetTemplateId);

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabUndo.cpp

@@ -35,8 +35,8 @@ namespace AzToolsFramework
         }
 
         void PrefabUndoInstance::Capture(
-            PrefabDom& initialState,
-            PrefabDom& endState,
+            const PrefabDom& initialState,
+            const PrefabDom& endState,
             const TemplateId& templateId)
         {
             m_templateId = templateId;
@@ -79,13 +79,16 @@ namespace AzToolsFramework
 
             //generate undo/redo patches
             m_instanceToTemplateInterface->GeneratePatch(m_redoPatch, initialState, endState);
+            m_instanceToTemplateInterface->AppendEntityAliasToPatchPaths(m_redoPatch, entityId);
             m_instanceToTemplateInterface->GeneratePatch(m_undoPatch, endState, initialState);
+            m_instanceToTemplateInterface->AppendEntityAliasToPatchPaths(m_undoPatch, entityId);
         }
 
         void PrefabUndoEntityUpdate::Undo()
         {
-            bool isPatchApplicationSuccessful =
-                m_instanceToTemplateInterface->PatchEntityInTemplate(m_undoPatch, m_entityAlias, m_templateId);
+            [[maybe_unused]] bool isPatchApplicationSuccessful =
+                m_instanceToTemplateInterface->PatchTemplate(m_undoPatch, m_templateId);
+
             AZ_Error(
                 "Prefab", isPatchApplicationSuccessful,
                 "Applying the undo patch on the entity with alias '%s' in template with id '%llu' was unsuccessful", m_entityAlias.c_str(),
@@ -94,8 +97,9 @@ namespace AzToolsFramework
 
         void PrefabUndoEntityUpdate::Redo()
         {
-            bool isPatchApplicationSuccessful =
-                m_instanceToTemplateInterface->PatchEntityInTemplate(m_redoPatch, m_entityAlias, m_templateId);
+            [[maybe_unused]] bool isPatchApplicationSuccessful =
+                m_instanceToTemplateInterface->PatchTemplate(m_redoPatch, m_templateId);
+
             AZ_Error(
                 "Prefab", isPatchApplicationSuccessful,
                 "Applying the redo patch on the entity with alias '%s' in template with id '%llu' was unsuccessful", m_entityAlias.c_str(),
@@ -120,7 +124,7 @@ namespace AzToolsFramework
             const TemplateId& targetId,
             const TemplateId& sourceId,
             const InstanceAlias& instanceAlias,
-            const PrefabDomReference linkDom,
+            PrefabDomReference linkDom,
             const LinkId linkId)
         {
             m_targetId = targetId;

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabUndo.h

@@ -51,8 +51,8 @@ namespace AzToolsFramework
             explicit PrefabUndoInstance(const AZStd::string& undoOperationName);
 
             void Capture(
-                PrefabDom& initialState,
-                PrefabDom& endState,
+                const PrefabDom& initialState,
+                const PrefabDom& endState,
                 const TemplateId& templateId);
 
             void Undo() override;
@@ -101,7 +101,7 @@ namespace AzToolsFramework
                 const TemplateId& targetId,
                 const TemplateId& sourceId,
                 const InstanceAlias& instanceAlias,
-                const PrefabDomReference linkDom = PrefabDomReference(),
+                PrefabDomReference linkDom = PrefabDomReference(),
                 const LinkId linkId = InvalidLinkId);
 
             void Undo() override;

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabUndoHelpers.cpp

@@ -0,0 +1,59 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#include <AzToolsFramework/Prefab/PrefabDomUtils.h>
+#include <AzToolsFramework/Prefab/PrefabUndo.h>
+#include <AzToolsFramework/API/ToolsApplicationAPI.h>
+
+namespace AzToolsFramework
+{
+    namespace Prefab
+    {
+        namespace PrefabUndoHelpers
+        {
+            void UpdatePrefabInstance(
+                const Instance& instance, AZStd::string_view undoMessage, const PrefabDom& instanceDomBeforeUpdate,
+                UndoSystem::URSequencePoint* undoBatch)
+            {
+                PrefabDom instanceDomAfterUpdate;
+                PrefabDomUtils::StoreInstanceInPrefabDom(instance, instanceDomAfterUpdate);
+
+                PrefabUndoInstance* state = aznew Prefab::PrefabUndoInstance(undoMessage);
+                state->Capture(instanceDomBeforeUpdate, instanceDomAfterUpdate, instance.GetTemplateId());
+                state->SetParent(undoBatch);
+                state->Redo();
+            }
+
+            void CreateLink(
+                TemplateId sourceTemplateId, TemplateId targetTemplateId, PrefabDomReference patch,
+                const InstanceAlias& instanceAlias, UndoSystem::URSequencePoint* undoBatch)
+            {
+                auto linkAddUndo = aznew PrefabUndoInstanceLink("Create Link");
+                linkAddUndo->Capture(targetTemplateId, sourceTemplateId, instanceAlias, patch, InvalidLinkId);
+                linkAddUndo->SetParent(undoBatch);
+                linkAddUndo->Redo();
+            }
+
+            void RemoveLink(
+                TemplateId sourceTemplateId, TemplateId targetTemplateId, const InstanceAlias& instanceAlias,
+                LinkId linkId, UndoSystem::URSequencePoint* undoBatch)
+            {
+                auto linkRemoveUndo = aznew PrefabUndoInstanceLink("Remove Link");
+                PrefabDom emptyLinkDom;
+                linkRemoveUndo->Capture(
+                    targetTemplateId, sourceTemplateId, instanceAlias, emptyLinkDom, linkId);
+                linkRemoveUndo->SetParent(undoBatch);
+                linkRemoveUndo->Redo();
+            }
+        }
+    } // namespace Prefab
+} // namespace AzToolsFramework

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabUndoHelpers.h

@@ -0,0 +1,32 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#pragma once
+
+namespace AzToolsFramework
+{
+    namespace Prefab
+    {
+        namespace PrefabUndoHelpers
+        {
+            void UpdatePrefabInstance(
+                const Instance& instance, AZStd::string_view undoMessage, const PrefabDom& instanceDomBeforeUpdate,
+                UndoSystem::URSequencePoint* undoBatch);
+            void CreateLink(
+                TemplateId sourceTemplateId, TemplateId targetTemplateId, PrefabDomReference patch,
+                const InstanceAlias& instanceAlias, UndoSystem::URSequencePoint* undoBatch);
+            void RemoveLink(
+                TemplateId sourceTemplateId, TemplateId targetTemplateId, const InstanceAlias& instanceAlias,
+                LinkId linkId, UndoSystem::URSequencePoint* undoBatch);
+        }
+    } // namespace Prefab
+} // namespace AzToolsFramework

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Spawnable/EditorInfoRemover.cpp

@@ -41,7 +41,7 @@ namespace AzToolsFramework::Prefab::PrefabConversionUtils
         }
 
         prefabProcessorContext.ListPrefabs(
-            [this, &serializeContext, &prefabProcessorContext](AZStd::string_view prefabName, PrefabDom& prefab)
+            [this, &serializeContext, &prefabProcessorContext]([[maybe_unused]] AZStd::string_view prefabName, PrefabDom& prefab)
             {
                 auto result = RemoveEditorInfo(prefab, serializeContext, prefabProcessorContext);
                 if (!result)

Code/Framework/AzToolsFramework/AzToolsFramework/PythonTerminal/ScriptHelpDialog.h

@@ -163,7 +163,8 @@ namespace AzToolsFramework
             QMainWindow* mainWindow = nullptr;
             for (QWidget* w : qApp->topLevelWidgets())
             {
-                if (mainWindow = qobject_cast<QMainWindow*>(w))
+                mainWindow = qobject_cast<QMainWindow*>(w);
+                if (mainWindow)
                 {
                     return mainWindow;
                 }

Code/Framework/AzToolsFramework/AzToolsFramework/Slice/SliceUtilities.cpp

@@ -2662,7 +2662,7 @@ namespace AzToolsFramework
                         QString cleanAssetSafeFolder(QDir::cleanPath(assetSafeFolder.c_str()));
                         // Compare using clean paths so slash direction does not matter.
                         // Note that this comparison is case sensitive because some file systems
-                        // Lumberyard supports are case sensitive.
+                        // Open 3D Engine supports are case sensitive.
                         if (cleanSaveAs.startsWith(cleanAssetSafeFolder))
                         {
                             isPathSafeForAssets = true;
@@ -4017,8 +4017,8 @@ namespace AzToolsFramework
                 // Detach entities action currently acts on entities and all descendants, so include those as part of the selection
                 AzToolsFramework::EntityIdList selectedDetachEntities(selectedTransformHierarchyEntities.begin(), selectedTransformHierarchyEntities.end());
 
-                // A selection in Lumberyard is usually singular, but a selection can have more than one entity.
-                // No Lumberyard systems support multiple selections, or multiple different groups of selected entities.
+                // A selection in Open 3D Engine is usually singular, but a selection can have more than one entity.
+                // No Open 3D Engine systems support multiple selections, or multiple different groups of selected entities.
                 QString detachEntitiesActionText(QObject::tr("Selection"));
                 QString detachEntitiesTooltipText;
                 if (selectedDetachEntities.size() == 1)

Code/Framework/AzToolsFramework/AzToolsFramework/SourceControl/PerforceComponent.cpp

@@ -71,7 +71,7 @@ namespace AzToolsFramework
         AZ_Assert(!s_perforceConn, "You may only have one Perforce component.\n");
         m_shutdownThreadSignal = false;
         m_waitingOnTrust = false;
-        m_autoChangelistDescription = "*Lumberyard Auto";
+        m_autoChangelistDescription = "*Open 3D Engine Auto";
         m_connectionState = SourceControlState::Disabled;
         m_validConnection = false;
         m_testConnection = false;

Code/Framework/AzToolsFramework/AzToolsFramework/Thumbnails/Thumbnail.cpp

@@ -10,12 +10,14 @@
 *
 */
 
+#include <AzToolsFramework/Thumbnails/ThumbnailerBus.h>
 #include <AzToolsFramework/Thumbnails/Thumbnail.h>
 AZ_PUSH_DISABLE_WARNING(4127 4251 4800 4244, "-Wunknown-warning-option") // 4127: conditional expression is constant
                                                                          // 4251: 'QTextCodec::ConverterState::flags': class 'QFlags<QTextCodec::ConversionFlag>' needs to have dll-interface to be used by clients of struct 'QTextCodec::ConverterState'
                                                                          // 4800: 'QTextBoundaryFinderPrivate *const ': forcing value to bool 'true' or 'false' (performance warning)
                                                                          // 4244: conversion from 'int' to 'qint8', possible loss of data
 #include <QtConcurrent/QtConcurrent>
+#include <QThreadPool>
 AZ_POP_DISABLE_WARNING
 
 namespace AzToolsFramework
@@ -80,7 +82,11 @@ namespace AzToolsFramework
             if (m_state == State::Unloaded)
             {
                 m_state = State::Loading;
-                QFuture<void> future = QtConcurrent::run([this](){ LoadThread(); });
+                QThreadPool* threadPool;
+                ThumbnailContextRequestBus::BroadcastResult(
+                    threadPool,
+                    &ThumbnailContextRequestBus::Handler::GetThreadPool);
+                QFuture<void> future = QtConcurrent::run(threadPool, [this](){ LoadThread(); });
                 m_watcher.setFuture(future);
             }
         }

Code/Framework/AzToolsFramework/AzToolsFramework/Thumbnails/ThumbnailContext.cpp

@@ -28,10 +28,15 @@ namespace AzToolsFramework
             : m_missingThumbnail(new MissingThumbnail(thumbnailSize))
             , m_loadingThumbnail(new LoadingThumbnail(thumbnailSize))
             , m_thumbnailSize(thumbnailSize)
+            , m_threadPool(this)
         {
+            ThumbnailContextRequestBus::Handler::BusConnect();
         }
 
-        ThumbnailContext::~ThumbnailContext() = default;
+        ThumbnailContext::~ThumbnailContext()
+        {
+            ThumbnailContextRequestBus::Handler::BusDisconnect();
+        }
 
         bool ThumbnailContext::IsLoading(SharedThumbnailKey key)
         {
@@ -53,6 +58,11 @@ namespace AzToolsFramework
             AzToolsFramework::AssetBrowser::AssetBrowserViewRequestBus::Broadcast(&AzToolsFramework::AssetBrowser::AssetBrowserViewRequests::Update);
         }
 
+        QThreadPool* ThumbnailContext::GetThreadPool()
+        {
+            return &m_threadPool;
+        }
+
         SharedThumbnail ThumbnailContext::GetThumbnail(SharedThumbnailKey key)
         {
             SharedThumbnail thumbnail;

Code/Framework/AzToolsFramework/AzToolsFramework/Thumbnails/ThumbnailContext.h

@@ -19,6 +19,7 @@
 
 #include <QObject>
 #include <QList>
+#include <QThreadPool>
 #endif
 
 class QString;
@@ -40,6 +41,7 @@ namespace AzToolsFramework
         */
         class ThumbnailContext
             : public QObject
+            , public ThumbnailContextRequestBus::Handler
         {
             Q_OBJECT
         public:
@@ -58,10 +60,13 @@ namespace AzToolsFramework
             void UnregisterThumbnailProvider(const char* providerName);
 
             void RedrawThumbnail();
-            
+
             //! Default context used for most thumbnails
             static constexpr const char* DefaultContext = "Default";
 
+            // ThumbnailContextRequestBus::Handler interface overrides...
+            QThreadPool* GetThreadPool() override;
+
         private:
             struct ProviderCompare {
                 bool operator() (const SharedThumbnailProvider& lhs, const SharedThumbnailProvider& rhs) const
@@ -79,6 +84,9 @@ namespace AzToolsFramework
             SharedThumbnail m_loadingThumbnail;
             //! Thumbnail size (width and height in pixels)
             int m_thumbnailSize;
+            //! There is only a limited number of threads on global threadPool, because there can be many thumbnails rendering at once
+            //! an individual threadPool is needed to avoid deadlocks
+            QThreadPool m_threadPool;
         };
     } // namespace Thumbnailer
 } // namespace AzToolsFramework

Code/Framework/AzToolsFramework/AzToolsFramework/Thumbnails/ThumbnailWidget.cpp

@@ -79,7 +79,12 @@ namespace AzToolsFramework
                 int realHeight = qMin(aznumeric_cast<int>(originalWidth /aspectRatio), originalHeight);
                 int realWidth = aznumeric_cast<int>(realHeight * aspectRatio);
                 int x = (originalWidth - realWidth) / 2;
-                painter.drawPixmap(QRect(x, 0, realHeight, realWidth), pixmap);
+                // pixmap needs to be manually scaled to produce smoother result and avoid looking pixelated
+                // using painter.setRenderHint(QPainter::SmoothPixmapTransform); does not seem to work
+                // Note: there is a potential issue with pixmap.scaled:
+                // it is multithreaded (using global threadPool) and blocking until finished.
+                // A deadlock will happen if global threadPool has no free threads available.
+                painter.drawPixmap(QPoint(x, 0), pixmap.scaled(realWidth, realHeight, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
             }
             QWidget::paintEvent(event);
         }

Code/Framework/AzToolsFramework/AzToolsFramework/Thumbnails/ThumbnailerBus.h

@@ -17,11 +17,23 @@
 #include <AzToolsFramework/Thumbnails/Thumbnail.h>
 
 class QPixmap;
+class QThreadPool;
 
 namespace AzToolsFramework
 {
     namespace Thumbnailer
     {
+        //! Interaction with thumbnail context
+        class ThumbnailContextRequests
+            : public AZ::EBusTraits
+        {
+        public:
+            //! Get thread pool for drawing thumbnails
+            virtual QThreadPool* GetThreadPool() = 0;
+        };
+
+        using ThumbnailContextRequestBus = AZ::EBus<ThumbnailContextRequests>;
+
         //! Interaction with thumbnailer
         class ThumbnailerRequests
             : public AZ::EBusTraits

Code/Framework/AzToolsFramework/AzToolsFramework/ToolsComponents/ComponentMimeData.cpp

@@ -24,7 +24,7 @@ namespace AzToolsFramework
 {
     QString ComponentTypeMimeData::GetMimeType()
     {
-        return "application/x-amazon-lumberyard-editorcomponenttypes";
+        return "application/x-amazon-o3de-editorcomponenttypes";
     }
 
     AZStd::unique_ptr<QMimeData> ComponentTypeMimeData::Create(const ClassDataContainer& container)
@@ -99,7 +99,7 @@ namespace AzToolsFramework
 
     QString ComponentMimeData::GetMimeType()
     {
-        return "application/x-amazon-lumberyard-editorcomponentdata";
+        return "application/x-amazon-o3de-editorcomponentdata";
     }
 
     AZStd::unique_ptr<QMimeData> ComponentMimeData::Create(const ComponentDataContainer& components)

Code/Framework/AzToolsFramework/AzToolsFramework/ToolsComponents/EditorComponentBase.h

@@ -15,7 +15,7 @@
  * Header file for the editor component base class.
  * Derive from this class to create a version of a component to use in the 
  * editor, as opposed to the version of the component that is used during run time. 
- * To learn more about editor components, see the [Lumberyard Developer Guide] 
+ * To learn more about editor components, see the [Open 3D Engine Developer Guide] 
  * (http://docs.aws.amazon.com/lumberyard/latest/developerguide/component-entity-system-pg-editor-components.html).
  */
 
@@ -52,7 +52,7 @@ namespace AzToolsFramework
          * To create one or more game components to represent your editor component 
          * in runtime, use BuildGameEntity(). 
          *
-         * To learn more about editor components, see the [Lumberyard Developer Guide]
+         * To learn more about editor components, see the [Open 3D Engine Developer Guide]
          * (http://docs.aws.amazon.com/lumberyard/latest/developerguide/component-entity-system-pg-editor-components.html).
          */
         class EditorComponentBase

Code/Framework/AzToolsFramework/AzToolsFramework/ToolsComponents/EditorLayerComponent.cpp

@@ -408,7 +408,7 @@ namespace AzToolsFramework
 
             QString fullLayerPath(layerFolder.filePath(myLayerFileName));
 
-            // Lumberyard will read in the layer in whatever format it's in, so there's no need to check what the save format is set to.
+            // Open 3D Engine will read in the layer in whatever format it's in, so there's no need to check what the save format is set to.
             // The save format is also set in this object that is being loaded, so it wouldn't even be available.
             m_loadedLayer = AZ::Utils::LoadObjectFromFile<EditorLayer>(fullLayerPath.toUtf8().data());
 
@@ -1051,7 +1051,6 @@ namespace AzToolsFramework
                 currentFailure));
 
             // FileIO doesn't support removing directory, so use Qt.
-            // QDir::IsEmpty isn't available until a newer version fo Qt than Lumberyard is using.
             if (layerTempFolder.entryInfoList(
                 QDir::NoDotAndDotDot | QDir::AllEntries | QDir::System | QDir::Hidden).count() == 0)
             {
@@ -1485,7 +1484,7 @@ namespace AzToolsFramework
 
             if (!newLayerEntityId.IsValid())
             {
-                return LayerResult(LayerResultStatus::Error, "Lumberyard was unable to create a layer entity.");
+                return LayerResult(LayerResultStatus::Error, "Open 3D Engine was unable to create a layer entity.");
             }
 
             // If this new layer has a parent, then set its parent.

Code/Framework/AzToolsFramework/AzToolsFramework/ToolsComponents/EditorLayerComponent.h

@@ -58,7 +58,7 @@ namespace AzToolsFramework
             AZ::Color m_color = AZ::Color::CreateOne();
             // Default to text files, so the save history is easier to understand in source control.
             // This attribute only effects writing layers, and is safe to store here instead of on the component.
-            // When reading files off disk, Lumberyard figures out the correct format automatically.
+            // When reading files off disk, Open 3D Engine figures out the correct format automatically.
             bool m_saveAsBinary = false;
 
             // The layer entity needs to be invisible to all other systems, so they don't show up in the viewport.
@@ -338,7 +338,7 @@ namespace AzToolsFramework
             EditorLayer* m_loadedLayer = nullptr;
             AZStd::string m_layerFileName;
 
-            // Lumberyard's serialization system requires everything in the editor to have a serialized to disk counterpart.
+            // Open 3D Engine's serialization system requires everything in the editor to have a serialized to disk counterpart.
             // Layers have their data split into two categories: Stuff that should save to the layer file, and stuff that should
             // save to the layer component in the level. To allow the layer component to edit the data that goes in the layer file,
             // a placeholder value is serialized. This is only used at edit time, and is copied and cleared during serialization.

Code/Framework/AzToolsFramework/AzToolsFramework/ToolsComponents/EditorNonUniformScaleComponent.cpp

@@ -13,6 +13,7 @@
 #include <AzToolsFramework/ToolsComponents/EditorNonUniformScaleComponent.h>
 #include <AzCore/Serialization/EditContext.h>
 #include <AzFramework/Components/NonUniformScaleComponent.h>
+#include <AzCore/Math/Transform.h>
 #include <AzCore/Math/ToString.h>
 
 namespace AzToolsFramework
@@ -44,7 +45,9 @@ namespace AzToolsFramework
                         ->DataElement(
                             AZ::Edit::UIHandlers::Default, &EditorNonUniformScaleComponent::m_scale, "Non-uniform Scale",
                             "Non-uniform scale for this entity only (does not propagate through hierarchy)")
-                        ->Attribute(AZ::Edit::Attributes::Min, AZ::MinNonUniformScale)
+                        ->Attribute(AZ::Edit::Attributes::Min, AZ::MinTransformScale)
+                        ->Attribute(AZ::Edit::Attributes::Max, AZ::MaxTransformScale)
+                        ->Attribute(AZ::Edit::Attributes::Step, 0.1f)
                         ->Attribute(AZ::Edit::Attributes::ChangeNotify, &EditorNonUniformScaleComponent::OnScaleChanged)
                         ;
                 }
@@ -106,13 +109,13 @@ namespace AzToolsFramework
 
         void EditorNonUniformScaleComponent::SetScale(const AZ::Vector3& scale)
         {
-            if (scale.GetMinElement() >= AZ::MinNonUniformScale)
+            if (scale.GetMinElement() >= AZ::MinTransformScale && scale.GetMaxElement() <= AZ::MaxTransformScale)
             {
                 m_scale = scale;
             }
             else
             {
-                AZ::Vector3 clampedScale = scale.GetMax(AZ::Vector3(AZ::MinNonUniformScale));
+                AZ::Vector3 clampedScale = scale.GetClamp(AZ::Vector3(AZ::MinTransformScale), AZ::Vector3(AZ::MaxTransformScale));
                 AZ_Warning("Editor Non-uniform Scale Component", false, "SetScale value was clamped from %s to %s for entity %s",
                     AZ::ToString(scale).c_str(), AZ::ToString(clampedScale).c_str(), GetEntity()->GetName().c_str());
                 m_scale = clampedScale;

Code/Framework/AzToolsFramework/AzToolsFramework/ToolsComponents/TransformComponent.cpp

@@ -1276,7 +1276,6 @@ namespace AzToolsFramework
                             Attribute(AZ::Edit::Attributes::SliceFlags, AZ::Edit::SliceFlags::NotPushableOnSliceRoot)->
                         DataElement(TransformScaleHandler, &EditorTransform::m_scale, "Scale", "Local Scale")->
                             Attribute(AZ::Edit::Attributes::Step, 0.1f)->
-                            Attribute(AZ::Edit::Attributes::Min, 0.01f)->
                             Attribute(AZ::Edit::Attributes::ReadOnly, &EditorTransform::m_locked)
                         ;
                 }

Code/Framework/AzToolsFramework/AzToolsFramework/ToolsComponents/TransformScalePropertyHandler.cpp

@@ -12,6 +12,7 @@
 
 #include "AzToolsFramework_precompiled.h"
 #include <ToolsComponents/TransformScalePropertyHandler.h>
+#include <AzCore/Math/Transform.h>
 #include <AzCore/Math/Vector3.h>
 
 namespace AzToolsFramework
@@ -36,8 +37,8 @@ namespace AzToolsFramework
                     AzToolsFramework::PropertyEditorGUIMessages::Bus::Broadcast(&AzToolsFramework::PropertyEditorGUIMessages::RequestWrite, newCtrl);
                 });
 
-            newCtrl->setMinimum(0.01f);
-            newCtrl->setMaximum(std::numeric_limits<float>::max());
+            newCtrl->setMinimum(AZ::MinTransformScale);
+            newCtrl->setMaximum(AZ::MaxTransformScale);
 
             return newCtrl;
         }

Code/Framework/AzToolsFramework/AzToolsFramework/UI/EditorEntityUi/EditorEntityUiHandlerBase.cpp

@@ -56,6 +56,16 @@ namespace AzToolsFramework
         return QPixmap();
     }
 
+    bool EditorEntityUiHandlerBase::CanToggleLockVisibility(AZ::EntityId /*entityId*/) const
+    {
+        return true;
+    }
+
+    bool EditorEntityUiHandlerBase::CanRename(AZ::EntityId /*entityId*/) const
+    {
+        return true;
+    }
+
     void EditorEntityUiHandlerBase::PaintItemBackground(QPainter* /*painter*/, const QStyleOptionViewItem& /*option*/, const QModelIndex& /*index*/) const
     {
     }

Code/Framework/AzToolsFramework/AzToolsFramework/UI/EditorEntityUi/EditorEntityUiHandlerBase.h

@@ -45,6 +45,10 @@ namespace AzToolsFramework
         virtual QString GenerateItemTooltip(AZ::EntityId entityId) const;
         //! Returns the item icon pixmap to display in the Outliner.
         virtual QPixmap GenerateItemIcon(AZ::EntityId entityId) const;
+        //! Returns whether the element's lock and visibility state should be accessible in the Outliner
+        virtual bool CanToggleLockVisibility(AZ::EntityId entityId) const;
+        //! Returns whether the element's name should be editable
+        virtual bool CanRename(AZ::EntityId entityId) const;
 
         //! Paints the background of the item in the Outliner.
         virtual void PaintItemBackground(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const;

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Layer/LayerUiHandler.cpp

@@ -97,8 +97,6 @@ namespace AzToolsFramework
         AzToolsFramework::Layers::EditorLayerComponentRequestBus::EventResult(
             layerColor, entityId, &AzToolsFramework::Layers::EditorLayerComponentRequestBus::Events::GetLayerColor);
 
-        const QTreeView* outlinerTreeView(qobject_cast<const QTreeView*>(option.widget));
-        int indentation = outlinerTreeView->indentation();
 
         bool isFirstColumn = index.column() == EntityOutlinerListModel::ColumnName;
         bool hasVisibleChildren = index.data(EntityOutlinerListModel::ExpandedRole).value<bool>() && index.model()->hasChildren(index);

Code/Framework/AzToolsFramework/AzToolsFramework/UI/LegacyFramework/Core/EditorFrameworkApplication.cpp

@@ -112,7 +112,6 @@ namespace LegacyFramework
         m_applicationEntity = NULL;
         m_ptrSystemEntity = NULL;
         m_applicationModule[0] = 0;
-        m_appRoot[0] = 0;
     }
 
     HMODULE Application::GetMainModule()
@@ -193,6 +192,10 @@ namespace LegacyFramework
         // if we're in console mode, listen for CTRL+C
         ::SetConsoleCtrlHandler(CTRL_BREAK_HandlerRoutine, true);
 #endif
+
+        m_ptrCommandLineParser = aznew AzFramework::CommandLine();
+        m_ptrCommandLineParser->Parse(m_desc.m_argc, m_desc.m_argv);
+
         // If we don't have one create a serialize context
         if (GetSerializeContext() == nullptr)
         {
@@ -490,15 +493,7 @@ namespace LegacyFramework
 
         AZ_Assert(!m_desc.m_enableProjectManager || m_desc.m_enableGUI, "Enabling the project manager in the application settings requires enabling the GUI as well.");
 
-        // if we're a GUI APP we need the UI Framework component:
-        if (m_desc.m_enableGUI)
-        {
-            EnsureComponentCreated(AzToolsFramework::Framework::RTTI_Type());
-        }
-        else
-        {
-            EnsureComponentCreated(AzToolsFramework::Framework::RTTI_Type());
-        }
+        EnsureComponentCreated(AzToolsFramework::Framework::RTTI_Type());
     }
 
     //=========================================================================

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Logging/NewLogTabDialog.cpp

@@ -16,7 +16,7 @@
 
 #include "NewLogTabDialog.h"
 AZ_PUSH_DISABLE_WARNING(4251, "-Wunknown-warning-option") // 4251: 'QLayoutItem::align': class 'QFlags<Qt::AlignmentFlag>' needs to have dll-interface to be used by clients of class 'QLayoutItem'
-#include <UI/Logging/ui_NewLogTabDialog.h>
+#include <AzToolsFramework/UI/Logging/ui_NewLogTabDialog.h>
 AZ_POP_DISABLE_WARNING
 #include <QPushButton>
 #include <QLineEdit>
@@ -97,4 +97,4 @@ namespace AzToolsFramework
     } // namespace LogPanel
 } // namespace AzToolsFramework
 
-#include "UI/Logging/moc_NewLogTabDialog.cpp"
+#include "UI/Logging/moc_NewLogTabDialog.cpp"

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Outliner/EntityOutlinerListModel.cpp

@@ -351,58 +351,68 @@ namespace AzToolsFramework
 
     QVariant EntityOutlinerListModel::dataForVisibility(const QModelIndex& index, int role) const
     {
-        auto id = GetEntityFromIndex(index);
+        auto entityId = GetEntityFromIndex(index);
+        auto entityUiHandler = m_editorEntityFrameworkInterface->GetHandler(entityId);
 
-        switch (role)
+        if (!entityUiHandler || entityUiHandler->CanToggleLockVisibility(entityId))
         {
+            switch (role)
+            {
             case Qt::CheckStateRole:
-            {
-                return IsEntitySetToBeVisible(id) ? Qt::Checked : Qt::Unchecked;
-            }
+                {
+                    return IsEntitySetToBeVisible(entityId) ? Qt::Checked : Qt::Unchecked;
+                }
             case Qt::ToolTipRole:
-            {
-                return QString("Show/Hide Entity");
-            }
+                {
+                    return QString("Show/Hide Entity");
+                }
             case Qt::SizeHintRole:
-            {
-                return QSize(20, 20);
+                {
+                    return QSize(20, 20);
+                }
             }
+            return dataForAll(index, role);
         }
 
-        return dataForAll(index, role);
+        return QVariant();
     }
 
     QVariant EntityOutlinerListModel::dataForLock(const QModelIndex& index, int role) const
     {
-        auto id = GetEntityFromIndex(index);
+        auto entityId = GetEntityFromIndex(index);
+        auto entityUiHandler = m_editorEntityFrameworkInterface->GetHandler(entityId);
 
-        switch (role)
+        if (!entityUiHandler || entityUiHandler->CanToggleLockVisibility(entityId))
         {
+            switch (role)
+            {
             case Qt::CheckStateRole:
-            {
-                bool isLocked = false;
-                // Lock state is tracked in 3 places:
-                // EditorLockComponent, EditorEntityModel, and ComponentEntityObject.
-                // In addition to that, entities that are in layers can have the layer's lock state override their own.
-                // Retrieving the lock state from the lock component is ideal for drawing the lock icon in the outliner because
-                // the outliner needs to show that specific entity's lock state, and not the actual final lock state including the layer behavior.
-                // The EditorLockComponent only knows about the specific entity's lock state and not the hierarchy.
-                EditorLockComponentRequestBus::EventResult(
-                    isLocked, id, &EditorLockComponentRequests::GetLocked);
+                {
+                    bool isLocked = false;
+                    // Lock state is tracked in 3 places:
+                    // EditorLockComponent, EditorEntityModel, and ComponentEntityObject.
+                    // In addition to that, entities that are in layers can have the layer's lock state override their own.
+                    // Retrieving the lock state from the lock component is ideal for drawing the lock icon in the outliner because
+                    // the outliner needs to show that specific entity's lock state, and not the actual final lock state including the layer
+                    // behavior. The EditorLockComponent only knows about the specific entity's lock state and not the hierarchy.
+                    EditorLockComponentRequestBus::EventResult(isLocked, entityId, &EditorLockComponentRequests::GetLocked);
 
-                return isLocked ? Qt::Checked : Qt::Unchecked;
-            }
+                    return isLocked ? Qt::Checked : Qt::Unchecked;
+                }
             case Qt::ToolTipRole:
-            {
-                return QString("Lock/Unlock Entity (Locked means the entity cannot be moved in the viewport)");
-            }
+                {
+                    return QString("Lock/Unlock Entity (Locked means the entity cannot be moved in the viewport)");
+                }
             case Qt::SizeHintRole:
-            {
-                return QSize(20, 20);
+                {
+                    return QSize(20, 20);
+                }
             }
+
+            return dataForAll(index, role);
         }
 
-        return dataForAll(index, role);
+        return QVariant();
     }
 
     QVariant EntityOutlinerListModel::dataForSortIndex(const QModelIndex& index, int role) const
@@ -429,8 +439,12 @@ namespace AzToolsFramework
             if (value.canConvert<Qt::CheckState>())
             {
                 const auto entityId = GetEntityFromIndex(index);
-                switch (index.column())
+                auto entityUiHandler = m_editorEntityFrameworkInterface->GetHandler(entityId);
+
+                if (!entityUiHandler || entityUiHandler->CanToggleLockVisibility(entityId))
                 {
+                    switch (index.column())
+                    {
                     case ColumnVisibilityToggle:
                         ToggleEntityVisibility(entityId);
                         break;
@@ -438,6 +452,7 @@ namespace AzToolsFramework
                     case ColumnLockToggle:
                         ToggleEntityLockState(entityId);
                         break;
+                    }
                 }
             }
         }
@@ -826,7 +841,6 @@ namespace AzToolsFramework
             for (const ComponentAssetPair& pair : componentAssetPairs)
             {
                 const AZ::TypeId& componentType = pair.first;
-                const AZ::Data::AssetId& assetId = pair.second;
 
                 componentsToAdd.push_back(componentType);
             }
@@ -853,7 +867,6 @@ namespace AzToolsFramework
             }
 
             // Assign asset associated with each created component.
-            const AZ::Entity::ComponentArrayType& componentsAdded = addComponentsOutcome.GetValue()[targetEntityId].m_componentsAdded;
             for (const ComponentAssetPair& pair : componentAssetPairs)
             {
                 const AZ::TypeId& componentType = pair.first;
@@ -932,6 +945,12 @@ namespace AzToolsFramework
             return false;
         }
 
+        // Disable reparenting to the root level
+        if (!newParentId.IsValid())
+        {
+            return false;
+        }
+
         // Ignore entities not owned by the editor context. It is assumed that all entities belong
         // to the same context since multiple selection doesn't span across views.
         for (const AZ::EntityId& entityId : selectedEntityIds)
@@ -961,39 +980,33 @@ namespace AzToolsFramework
                 }
             }
 
-            if (newParentId.IsValid())
+            bool isLayerEntity = false;
+            Layers::EditorLayerComponentRequestBus::EventResult(
+                isLayerEntity,
+                entityId,
+                &Layers::EditorLayerComponentRequestBus::Events::HasLayer);
+            // Layers can only have other layers as parents, or have no parent.
+            if (isLayerEntity)
             {
-                bool isLayerEntity = false;
+                bool newParentIsLayer = false;
                 Layers::EditorLayerComponentRequestBus::EventResult(
-                    isLayerEntity,
-                    entityId,
+                    newParentIsLayer,
+                    newParentId,
                     &Layers::EditorLayerComponentRequestBus::Events::HasLayer);
-                // Layers can only have other layers as parents, or have no parent.
-                if (isLayerEntity)
+                if (!newParentIsLayer)
                 {
-                    bool newParentIsLayer = false;
-                    Layers::EditorLayerComponentRequestBus::EventResult(
-                        newParentIsLayer,
-                        newParentId,
-                        &Layers::EditorLayerComponentRequestBus::Events::HasLayer);
-                    if (!newParentIsLayer)
-                    {
-                        return false;
-                    }
+                    return false;
                 }
             }
         }
 
         //Only check the entity pointer if the entity id is valid because
         //we want to allow dragging items to unoccupied parts of the tree to un-parent them
-        if (newParentId.IsValid())
+        AZ::Entity* newParentEntity = nullptr;
+        AZ::ComponentApplicationBus::BroadcastResult(newParentEntity, &AZ::ComponentApplicationRequests::FindEntity, newParentId);
+        if (!newParentEntity)
         {
-            AZ::Entity* newParentEntity = nullptr;
-            AZ::ComponentApplicationBus::BroadcastResult(newParentEntity, &AZ::ComponentApplicationRequests::FindEntity, newParentId);
-            if (!newParentEntity)
-            {
-                return false;
-            }
+            return false;
         }
 
         //reject dragging on to yourself or your children
@@ -1331,14 +1344,15 @@ namespace AzToolsFramework
         emit EnableSelectionUpdates(false);
         auto parentIndex = GetIndexFromEntity(parentId);
         auto childIndex = GetIndexFromEntity(childId);
-        beginRemoveRows(parentIndex, childIndex.row(), childIndex.row());
+        beginResetModel();
     }
 
     void EntityOutlinerListModel::OnEntityInfoUpdatedRemoveChildEnd(AZ::EntityId parentId, AZ::EntityId childId)
     {
         (void)childId;
         AZ_PROFILE_FUNCTION(AZ::Debug::ProfileCategory::AzToolsFramework);
-        endRemoveRows();
+
+        endResetModel();
 
         //must refresh partial lock/visibility of parents
         m_isFilterDirty = true;
@@ -1978,7 +1992,8 @@ namespace AzToolsFramework
         }
 
         // Retrieve the Entity UI Handler
-        AZ::EntityId entityId(index.data(EntityOutlinerListModel::EntityIdRole).value<AZ::u64>());
+        auto firstColumnIndex = index.siblingAtColumn(0);
+        AZ::EntityId entityId(firstColumnIndex.data(EntityOutlinerListModel::EntityIdRole).value<AZ::u64>());
         auto entityUiHandler = m_editorEntityFrameworkInterface->GetHandler(entityId);
 
         const bool isSelected = (option.state & QStyle::State_Selected);
@@ -2001,8 +2016,11 @@ namespace AzToolsFramework
             case EntityOutlinerListModel::ColumnVisibilityToggle:
             case EntityOutlinerListModel::ColumnLockToggle:
             {
-                // Paint the Visibility and Lock state checkboxes
-                PaintCheckboxes(painter, option, index, isHovered);
+                if (!entityUiHandler || entityUiHandler->CanToggleLockVisibility(entityId))
+                {
+                    // Paint the Visibility and Lock state checkboxes
+                    PaintCheckboxes(painter, option, index, isHovered);
+                }
             }
             break;
             case EntityOutlinerListModel::ColumnName:

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Outliner/EntityOutlinerWidget.cpp

@@ -30,6 +30,7 @@
 #include <AzToolsFramework/Entity/EditorEntityHelpers.h>
 #include <AzToolsFramework/Entity/EditorEntityInfoBus.h>
 #include <AzToolsFramework/UI/ComponentPalette/ComponentPaletteUtil.hxx>
+#include <AzToolsFramework/UI/EditorEntityUi/EditorEntityUiHandlerBase.h>
 #include <AzToolsFramework/UI/Outliner/EntityOutlinerDisplayOptionsMenu.h>
 #include <AzToolsFramework/UI/Outliner/EntityOutlinerListModel.hxx>
 #include <AzToolsFramework/UI/Outliner/EntityOutlinerSortFilterProxyModel.hxx>
@@ -49,7 +50,7 @@
 #include <QTimer>
 #include <QToolButton>
 
-#include <UI/Outliner/ui_EntityOutlinerWidget.h>
+#include <AzToolsFramework/UI/Outliner/ui_EntityOutlinerWidget.h>
 
 namespace
 {
@@ -184,6 +185,7 @@ namespace AzToolsFramework
         m_gui->m_objectTree->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
         m_gui->m_objectTree->setAutoScrollMargin(20);
         m_gui->m_objectTree->setIndentation(24);
+        m_gui->m_objectTree->setRootIsDecorated(false);
         connect(m_gui->m_objectTree, &QTreeView::customContextMenuRequested, this, &EntityOutlinerWidget::OnOpenTreeContextMenu);
 
         // custom item delegate
@@ -270,6 +272,12 @@ namespace AzToolsFramework
 
         m_listModel->Initialize();
 
+        m_editorEntityUiInterface = AZ::Interface<AzToolsFramework::EditorEntityUiInterface>::Get();
+
+        AZ_Assert(
+            m_editorEntityUiInterface != nullptr,
+            "EntityOutlinerWidget requires a EditorEntityUiInterface instance on Initialize.");
+
         EditorPickModeNotificationBus::Handler::BusConnect(GetEntityContextId());
         EntityHighlightMessages::Bus::Handler::BusConnect();
         EntityOutlinerModelNotificationBus::Handler::BusConnect();
@@ -561,7 +569,13 @@ namespace AzToolsFramework
 
             if (m_selectedEntityIds.size() == 1)
             {
-                contextMenu->addAction(m_actionToRenameSelection);
+                auto entityId = m_selectedEntityIds.front();
+                auto entityUiHandler = m_editorEntityUiInterface->GetHandler(entityId);
+
+                if (!entityUiHandler || entityUiHandler->CanRename(entityId))
+                {
+                    contextMenu->addAction(m_actionToRenameSelection);
+                }
             }
 
             if (m_selectedEntityIds.size() == 1)
@@ -687,11 +701,17 @@ namespace AzToolsFramework
 
         if (m_selectedEntityIds.size() == 1)
         {
-            const QModelIndex proxyIndex = GetIndexFromEntityId(m_selectedEntityIds.front());
-            if (proxyIndex.isValid())
+            auto entityId = m_selectedEntityIds.front();
+            auto entityUiHandler = m_editorEntityUiInterface->GetHandler(entityId);
+
+            if (!entityUiHandler || entityUiHandler->CanRename(entityId))
             {
-                m_gui->m_objectTree->setCurrentIndex(proxyIndex);
-                m_gui->m_objectTree->QTreeView::edit(proxyIndex);
+                const QModelIndex proxyIndex = GetIndexFromEntityId(entityId);
+                if (proxyIndex.isValid())
+                {
+                    m_gui->m_objectTree->setCurrentIndex(proxyIndex);
+                    m_gui->m_objectTree->QTreeView::edit(proxyIndex);
+                }
             }
         }
     }
@@ -804,10 +824,10 @@ namespace AzToolsFramework
         addAction(m_actionToDeleteSelectionAndDescendants);
 
         m_actionToRenameSelection = new QAction(tr("Rename"), this);
-    #ifdef Q_OS_MAC
+    #if defined(Q_OS_MAC)
         // "Alt+Return" translates to Option+Return on macOS
         m_actionToRenameSelection->setShortcut(tr("Alt+Return"));
-#elseif Q_OS_WIN
+    #elif defined(Q_OS_WIN)
         m_actionToRenameSelection->setShortcut(tr("F2"));
     #endif
         m_actionToRenameSelection->setShortcutContext(Qt::WidgetWithChildrenShortcut);
@@ -1089,16 +1109,6 @@ namespace AzToolsFramework
         setEnabled(true);
         SetEntityOutlinerState(m_gui, true);
     }
-
-    void EntityOutlinerWidget::SetRootEntity(AZ::EntityId rootEntityId)
-    {
-        // The proxy model needs a tick to initialize, else it will return an invalid index in mapFromSource.
-        QTimer::singleShot(0, this, [rootEntityId, this]() {
-            QModelIndex rootIndex = m_listModel->GetIndexFromEntity(rootEntityId);
-            QModelIndex proxyIndex = m_proxyModel->mapFromSource(rootIndex);
-            m_gui->m_objectTree->setRootIndex(proxyIndex);
-        });
-    }
     
     void EntityOutlinerWidget::SetUpdatesEnabled(bool enable)
     {
@@ -1114,6 +1124,12 @@ namespace AzToolsFramework
         }
     }
 
+    void EntityOutlinerWidget::ExpandEntityChildren(AZ::EntityId entityId)
+    {
+        QModelIndex index = GetIndexFromEntityId(entityId);
+        m_gui->m_objectTree->expand(index);
+    }
+
     void EntityOutlinerWidget::OnEntityInfoUpdatedAddChildEnd(AZ::EntityId /*parentId*/, AZ::EntityId childId)
     {
         QueueContentUpdateSort(childId);

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Outliner/EntityOutlinerWidget.hxx

@@ -42,6 +42,7 @@ namespace Ui
 
 namespace AzToolsFramework
 {
+    class EditorEntityUiInterface;
     class EntityOutlinerListModel;
     class EntityOutlinerSortFilterProxyModel;
 
@@ -106,8 +107,8 @@ namespace AzToolsFramework
         void LeftComponentMode(const AZStd::vector<AZ::Uuid>& componentModeTypes) override;
 
         // EntityOutlinerWidgetInterface
-        void SetRootEntity(AZ::EntityId rootEntityId) override;
         void SetUpdatesEnabled(bool enable) override;
+        void ExpandEntityChildren(AZ::EntityId entityId) override;
 
         // Build a selection object from the given entities. Entities already in the Widget's selection buffers are ignored.
         template <class EntityIdCollection>
@@ -193,6 +194,8 @@ namespace AzToolsFramework
         EntityIdSet m_entitiesToSort;
         EntityOutliner::DisplaySortMode m_sortMode;
         bool m_sortContentQueued;
+
+        EditorEntityUiInterface* m_editorEntityUiInterface = nullptr;
     };
 
 }

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Outliner/EntityOutlinerWidgetInterface.h

@@ -22,8 +22,8 @@ namespace AzToolsFramework
     public:
         AZ_RTTI(EntityOutlinerWidgetInterface, "{30C0F252-EC84-4196-BF59-EB9E73B8ADCB}");
 
-        virtual void SetRootEntity(AZ::EntityId rootEntityId) = 0;
         virtual void SetUpdatesEnabled(bool enable) = 0;
+        virtual void ExpandEntityChildren(AZ::EntityId entityId) = 0;
     };
 
 } // namespace AzToolsFramework

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/LevelRootUiHandler.cpp

@@ -0,0 +1,98 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include <AzToolsFramework/UI/Prefab/LevelRootUiHandler.h>
+
+#include <AzToolsFramework/UI/Prefab/PrefabEditInterface.h>
+#include <AzToolsFramework/Prefab/PrefabPublicInterface.h>
+#include <AzToolsFramework/UI/Outliner/EntityOutlinerListModel.hxx>
+
+#include <QAbstractItemModel>
+#include <QPainter>
+#include <QPainterPath>
+#include <QTreeView>
+
+namespace AzToolsFramework
+{
+    const QColor LevelRootUiHandler::m_levelRootBorderColor = QColor("#656565");
+    const QString LevelRootUiHandler::m_levelRootIconPath = QString(":/Level/level.svg");
+
+    LevelRootUiHandler::LevelRootUiHandler()
+    {
+        m_prefabEditInterface = AZ::Interface<Prefab::PrefabEditInterface>::Get();
+
+        if (m_prefabEditInterface == nullptr)
+        {
+            AZ_Assert(false, "LevelRootUiHandler - could not get PrefabEditInterface on LevelRootUiHandler construction.");
+            return;
+        }
+
+        m_prefabPublicInterface = AZ::Interface<Prefab::PrefabPublicInterface>::Get();
+
+        if (m_prefabPublicInterface == nullptr)
+        {
+            AZ_Assert(false, "LevelRootUiHandler - could not get PrefabPublicInterface on LevelRootUiHandler construction.");
+            return;
+        }
+    }
+
+    QPixmap LevelRootUiHandler::GenerateItemIcon(AZ::EntityId /*entityId*/) const
+    {
+        return QPixmap(m_levelRootIconPath);
+    }
+
+    QString LevelRootUiHandler::GenerateItemInfoString(AZ::EntityId entityId) const
+    {
+        QString infoString;
+
+        AZ::IO::Path path = m_prefabPublicInterface->GetOwningInstancePrefabPath(entityId);
+
+        if (!path.empty())
+        {
+            infoString =
+                QObject::tr("<span style=\"font-style: italic; font-weight: 400;\">(%1)</span>").arg(path.Filename().Native().data());
+        }
+
+        return infoString;
+    }
+
+    bool LevelRootUiHandler::CanToggleLockVisibility(AZ::EntityId /*entityId*/) const
+    {
+        return false;
+    }
+
+    bool LevelRootUiHandler::CanRename(AZ::EntityId /*entityId*/) const
+    {
+        return false;
+    }
+
+    void LevelRootUiHandler::PaintItemBackground(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& /*index*/) const
+    {
+        if (!painter)
+        {
+            AZ_Warning("LevelRootUiHandler", false, "LevelRootUiHandler - painter is nullptr, can't draw Prefab outliner background.");
+            return;
+        }
+
+        QPen borderLinePen(m_levelRootBorderColor, m_levelRootBorderThickness);
+
+        QRect rect = option.rect;
+        rect.setLeft(rect.left() + (m_levelRootBorderThickness / 2));
+
+        painter->save();
+        painter->setRenderHint(QPainter::Antialiasing, true);
+        painter->setPen(borderLinePen);
+        
+        // Draw border at the bottom
+        painter->drawLine(rect.bottomLeft(), rect.bottomRight());
+    }
+}

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/LevelRootUiHandler.h

@@ -0,0 +1,51 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#pragma once
+
+#include <AzToolsFramework/UI/EditorEntityUi/EditorEntityUiHandlerBase.h>
+
+namespace AzToolsFramework
+{
+    namespace Prefab
+    {
+        class PrefabEditInterface;
+        class PrefabPublicInterface;
+    };
+
+    class LevelRootUiHandler
+        : public EditorEntityUiHandlerBase
+    {
+    public:
+        AZ_CLASS_ALLOCATOR(LevelRootUiHandler, AZ::SystemAllocator, 0);
+        AZ_RTTI(AzToolsFramework::LevelRootUiHandler, "{B1D3B270-CD29-4033-873A-D78E76AB24A4}", EditorEntityUiHandlerBase);
+
+        LevelRootUiHandler();
+        ~LevelRootUiHandler() override = default;
+
+        // EditorEntityUiHandler...
+        QPixmap GenerateItemIcon(AZ::EntityId entityId) const override;
+        QString GenerateItemInfoString(AZ::EntityId entityId) const override;
+        bool CanToggleLockVisibility(AZ::EntityId entityId) const override;
+        bool CanRename(AZ::EntityId entityId) const override;
+        void PaintItemBackground(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const override;
+
+    private:
+        Prefab::PrefabEditInterface* m_prefabEditInterface = nullptr;
+        Prefab::PrefabPublicInterface* m_prefabPublicInterface = nullptr;
+
+        static constexpr int m_levelRootBorderThickness = 1;
+        static const QColor m_levelRootBorderColor;
+        static const QString m_levelRootIconPath;
+
+    };
+} // namespace AzToolsFramework

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabIntegrationManager.cpp

@@ -24,6 +24,7 @@
 #include <AzToolsFramework/AssetBrowser/AssetBrowserBus.h>
 #include <AzToolsFramework/AssetBrowser/AssetSelectionModel.h>
 #include <AzToolsFramework/AssetBrowser/Entries/SourceAssetBrowserEntry.h>
+#include <AzToolsFramework/Prefab/PrefabLoaderInterface.h>
 #include <AzToolsFramework/ToolsComponents/EditorLayerComponentBus.h>
 #include <AzToolsFramework/UI/EditorEntityUi/EditorEntityUiInterface.h>
 #include <AzToolsFramework/UI/Prefab/PrefabIntegrationInterface.h>
@@ -39,9 +40,12 @@ namespace AzToolsFramework
 {
     namespace Prefab
     {
+        
         EditorEntityUiInterface* PrefabIntegrationManager::s_editorEntityUiInterface = nullptr;
         PrefabPublicInterface* PrefabIntegrationManager::s_prefabPublicInterface = nullptr;
         PrefabEditInterface* PrefabIntegrationManager::s_prefabEditInterface = nullptr;
+        PrefabLoaderInterface* PrefabIntegrationManager::s_prefabLoaderInterface = nullptr;
+
         const AZStd::string PrefabIntegrationManager::s_prefabFileExtension = ".prefab";
 
         void PrefabUserSettings::Reflect(AZ::ReflectContext* context)
@@ -79,6 +83,13 @@ namespace AzToolsFramework
                 return;
             }
 
+            s_prefabLoaderInterface = AZ::Interface<PrefabLoaderInterface>::Get();
+            if (s_prefabLoaderInterface == nullptr)
+            {
+                AZ_Assert(false, "Prefab - could not get PrefabLoaderInterface on PrefabIntegrationManager construction.");
+                return;
+            }
+
             EditorContextMenuBus::Handler::BusConnect();
             PrefabInstanceContainerNotificationBus::Handler::BusConnect();
             AZ::Interface<PrefabIntegrationInterface>::Register(this);
@@ -130,14 +141,14 @@ namespace AzToolsFramework
             AzFramework::ApplicationRequests::Bus::BroadcastResult(
                 prefabWipFeaturesEnabled, &AzFramework::ApplicationRequests::ArePrefabWipFeaturesEnabled);
 
+            AzToolsFramework::EntityIdList selectedEntities;
+            AzToolsFramework::ToolsApplicationRequestBus::BroadcastResult(
+                selectedEntities, &AzToolsFramework::ToolsApplicationRequests::GetSelectedEntities);
+
             if (prefabWipFeaturesEnabled)
             {
                 // Create Prefab
                 {
-                    AzToolsFramework::EntityIdList selectedEntities;
-                    AzToolsFramework::ToolsApplicationRequestBus::BroadcastResult(
-                        selectedEntities, &AzToolsFramework::ToolsApplicationRequests::GetSelectedEntities);
-
                     if (!selectedEntities.empty())
                     {
                         bool layerInSelection = false;
@@ -186,10 +197,6 @@ namespace AzToolsFramework
 
             // Edit/Save Prefab
             {
-                AzToolsFramework::EntityIdList selectedEntities;
-                AzToolsFramework::ToolsApplicationRequestBus::BroadcastResult(
-                    selectedEntities, &AzToolsFramework::ToolsApplicationRequests::GetSelectedEntities);
-
                 if (selectedEntities.size() == 1)
                 {
                     AZ::EntityId selectedEntity = selectedEntities[0];
@@ -237,6 +244,14 @@ namespace AzToolsFramework
             {
                 menu->addSeparator();
             }
+
+            QAction* deleteAction = menu->addAction(QObject::tr("Delete"));
+            QObject::connect(deleteAction, &QAction::triggered, deleteAction, [this] { ContextMenu_DeleteSelected(); });
+            if (selectedEntities.size() == 0 ||
+                (selectedEntities.size() == 1 && s_prefabPublicInterface->IsLevelInstanceContainerEntity(selectedEntities[0])))
+            {
+                deleteAction->setDisabled(true);
+            }
         }
 
         void PrefabIntegrationManager::HandleSourceFileType(AZStd::string_view sourceFilePath, AZ::EntityId parentId, AZ::Vector3 position) const
@@ -316,14 +331,15 @@ namespace AzToolsFramework
 
                 GenerateSuggestedFilenameFromEntities(prefabRootEntities, suggestedName);
 
-                if (!QueryUserForPrefabSaveLocation(suggestedName, targetDirectory, AZ_CRC("PrefabUserSettings"), activeWindow, prefabName, prefabFilePath))
+                if (!QueryUserForPrefabSaveLocation(
+                        suggestedName, targetDirectory, AZ_CRC("PrefabUserSettings"), activeWindow, prefabName, prefabFilePath))
                 {
                     // User canceled prefab creation, or error prevented continuation.
                     return;
                 }
             }
 
-            auto createPrefabOutcome = s_prefabPublicInterface->CreatePrefab(selectedEntities, prefabFilePath);
+            auto createPrefabOutcome = s_prefabPublicInterface->CreatePrefab(selectedEntities, s_prefabLoaderInterface->GetRelativePathToProject(prefabFilePath.data()));
 
             if (!createPrefabOutcome.IsSuccess())
             {
@@ -369,6 +385,16 @@ namespace AzToolsFramework
             }
         }
 
+        void PrefabIntegrationManager::ContextMenu_DeleteSelected()
+        {
+            AzToolsFramework::EntityIdList selectedEntityIds;
+            AzToolsFramework::ToolsApplicationRequestBus::BroadcastResult(
+                selectedEntityIds, &AzToolsFramework::ToolsApplicationRequests::GetSelectedEntities);
+
+            AzToolsFramework::ToolsApplicationRequestBus::Broadcast(
+                &AzToolsFramework::ToolsApplicationRequests::DeleteEntitiesAndAllDescendants, selectedEntityIds);
+        }
+
         void PrefabIntegrationManager::GenerateSuggestedFilenameFromEntities(const EntityIdList& entityIds, AZStd::string& outName)
         {
             AZ_PROFILE_FUNCTION(AZ::Debug::ProfileCategory::AzToolsFramework);
@@ -630,7 +656,7 @@ namespace AzToolsFramework
                     QString cleanAssetSafeFolder(QDir::cleanPath(assetSafeFolder.c_str()));
                     // Compare using clean paths so slash direction does not matter.
                     // Note that this comparison is case sensitive because some file systems
-                    // Lumberyard supports are case sensitive.
+                    // Open 3D Engine supports are case sensitive.
                     if (cleanSaveAs.startsWith(cleanAssetSafeFolder))
                     {
                         isPathSafeForAssets = true;
@@ -972,7 +998,14 @@ namespace AzToolsFramework
 
         void PrefabIntegrationManager::OnPrefabComponentActivate(AZ::EntityId entityId)
         {
-            s_editorEntityUiInterface->RegisterEntity(entityId, m_prefabUiHandler.GetHandlerId());
+            if (s_prefabPublicInterface->IsLevelInstanceContainerEntity(entityId))
+            {
+                s_editorEntityUiInterface->RegisterEntity(entityId, m_levelRootUiHandler.GetHandlerId());
+            }
+            else
+            {
+                s_editorEntityUiInterface->RegisterEntity(entityId, m_prefabUiHandler.GetHandlerId());
+            }
         }
 
         void PrefabIntegrationManager::OnPrefabComponentDeactivate(AZ::EntityId entityId)

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabIntegrationManager.h

@@ -19,6 +19,7 @@
 #include <AzToolsFramework/AssetBrowser/AssetBrowserSourceDropBus.h>
 #include <AzToolsFramework/Editor/EditorContextMenuBus.h>
 #include <AzToolsFramework/Prefab/PrefabPublicInterface.h>
+#include <AzToolsFramework/UI/Prefab/LevelRootUiHandler.h>
 #include <AzToolsFramework/UI/Prefab/PrefabEditManager.h>
 #include <AzToolsFramework/UI/Prefab/PrefabIntegrationBus.h>
 #include <AzToolsFramework/UI/Prefab/PrefabIntegrationInterface.h>
@@ -28,6 +29,9 @@ namespace AzToolsFramework
 {
     namespace Prefab
     {
+
+        class PrefabLoaderInterface;
+
         //! Structure for saving/retrieving user settings related to prefab workflows.
         class PrefabUserSettings
             : public AZ::UserSettings
@@ -77,6 +81,9 @@ namespace AzToolsFramework
             // Manages the Edit Mode UI for prefabs
             PrefabEditManager m_prefabEditManager;
 
+            // Used to handle the UI for the level root
+            LevelRootUiHandler m_levelRootUiHandler;
+
             // Used to handle the UI for prefab entities
             PrefabUiHandler m_prefabUiHandler;
 
@@ -85,6 +92,7 @@ namespace AzToolsFramework
             static void ContextMenu_InstantiatePrefab();
             static void ContextMenu_EditPrefab(AZ::EntityId containerEntity);
             static void ContextMenu_SavePrefab(AZ::EntityId containerEntity);
+            static void ContextMenu_DeleteSelected();
 
             // Prompt and resolve dialogs
             static bool QueryUserForPrefabSaveLocation(
@@ -124,6 +132,7 @@ namespace AzToolsFramework
             static EditorEntityUiInterface* s_editorEntityUiInterface;
             static PrefabPublicInterface* s_prefabPublicInterface;
             static PrefabEditInterface* s_prefabEditInterface;
+            static PrefabLoaderInterface* s_prefabLoaderInterface;
         };
     }
 }

Code/Framework/AzToolsFramework/AzToolsFramework/UI/PropertyEditor/EntityPropertyEditor.cpp

@@ -100,7 +100,7 @@ AZ_PUSH_DISABLE_WARNING(4244 4251 4800, "-Wunknown-warning-option") // 4244: con
 #include <QTimer>
 AZ_POP_DISABLE_WARNING
 
-#include <UI/PropertyEditor/ui_EntityPropertyEditor.h>
+#include <AzToolsFramework/UI/PropertyEditor/ui_EntityPropertyEditor.h>
 
 // This has to live outside of any namespaces due to issues on Linux with calls to Q_INIT_RESOURCE if they are inside a namespace
 void initEntityPropertyEditorResources()
@@ -310,6 +310,9 @@ namespace AzToolsFramework
     {
         initEntityPropertyEditorResources();
 
+        m_prefabPublicInterface = AZ::Interface<Prefab::PrefabPublicInterface>::Get();
+        AZ_Assert(m_prefabPublicInterface != nullptr, "EntityPropertyEditor requires a PrefabPublicInterface instance on Initialize.");
+
         setObjectName("EntityPropertyEditor");
         setAcceptDrops(true);
 
@@ -405,8 +408,6 @@ namespace AzToolsFramework
         CreateActions();
         UpdateContents();
 
-        m_prefabPublicInterface = AZ::Interface<Prefab::PrefabPublicInterface>::Get();
-
         EditorEntityContextNotificationBus::Handler::BusConnect();
 
         //forced to register global event filter with application for selection
@@ -693,11 +694,38 @@ namespace AzToolsFramework
         m_gui->m_entityIcon->repaint();
     }
 
+    EntityPropertyEditor::InspectorLayout EntityPropertyEditor::GetCurrentInspectorLayout() const
+    {
+        if (!m_prefabsAreEnabled)
+        {
+            return m_isLevelEntityEditor ? InspectorLayout::LEVEL : InspectorLayout::ENTITY;
+        }
+
+        AZ::EntityId levelContainerEntityId = m_prefabPublicInterface->GetLevelInstanceContainerEntityId();
+        if (AZStd::find(m_selectedEntityIds.begin(), m_selectedEntityIds.end(), levelContainerEntityId) != m_selectedEntityIds.end())
+        {
+            if (m_selectedEntityIds.size() > 1)
+            {
+                return InspectorLayout::INVALID;
+            }
+            else
+            {
+                return InspectorLayout::LEVEL;
+            }
+        }
+        else
+        {
+            return InspectorLayout::ENTITY;
+        }
+    }
+
     void EntityPropertyEditor::UpdateEntityDisplay()
     {
         UpdateStatusComboBox();
 
-        if (m_isLevelEntityEditor)
+        InspectorLayout layout = GetCurrentInspectorLayout();
+
+        if (layout == InspectorLayout::LEVEL)
         {
             AZStd::string levelName;
             AzToolsFramework::EditorRequestBus::BroadcastResult(levelName, &AzToolsFramework::EditorRequests::GetLevelName);
@@ -737,13 +765,20 @@ namespace AzToolsFramework
         AZ_PROFILE_FUNCTION(AZ::Debug::ProfileCategory::AzToolsFramework);
         SelectionEntityTypeInfo result = SelectionEntityTypeInfo::None;
 
-        if (m_isLevelEntityEditor)
+        InspectorLayout layout = GetCurrentInspectorLayout();
+
+        if (layout == InspectorLayout::LEVEL)
         {
             // The Level Inspector should only have a list of selectable components after the
             // level entity itself is valid (i.e. "selected").
             return selection.empty() ? SelectionEntityTypeInfo::None : SelectionEntityTypeInfo::LevelEntity;
         }
 
+        if (layout == InspectorLayout::INVALID)
+        {
+            return SelectionEntityTypeInfo::Mixed;
+        }
+
         for (AZ::EntityId selectedEntityId : selection)
         {
             bool isLayerEntity = false;
@@ -909,16 +944,18 @@ namespace AzToolsFramework
             }
         }
 
+        bool isLevelLayout = GetCurrentInspectorLayout() == InspectorLayout::LEVEL;
+
         m_gui->m_entityDetailsLabel->setText(entityDetailsLabelText);
         m_gui->m_entityDetailsLabel->setVisible(entityDetailsVisible);
         m_gui->m_entityNameEditor->setVisible(hasEntitiesDisplayed);
         m_gui->m_entityNameLabel->setVisible(hasEntitiesDisplayed);
         m_gui->m_entityIcon->setVisible(hasEntitiesDisplayed);
-        m_gui->m_pinButton->setVisible(m_overrideSelectedEntityIds.empty() && hasEntitiesDisplayed && !m_isSystemEntityEditor && !m_isLevelEntityEditor);
-        m_gui->m_statusLabel->setVisible(hasEntitiesDisplayed && !m_isSystemEntityEditor && !m_isLevelEntityEditor);
-        m_gui->m_statusComboBox->setVisible(hasEntitiesDisplayed && !m_isSystemEntityEditor && !m_isLevelEntityEditor);
-        m_gui->m_entityIdLabel->setVisible(hasEntitiesDisplayed && !m_isSystemEntityEditor && !m_isLevelEntityEditor);
-        m_gui->m_entityIdText->setVisible(hasEntitiesDisplayed && !m_isSystemEntityEditor && !m_isLevelEntityEditor);
+        m_gui->m_pinButton->setVisible(m_overrideSelectedEntityIds.empty() && hasEntitiesDisplayed && !m_isSystemEntityEditor);
+        m_gui->m_statusLabel->setVisible(hasEntitiesDisplayed && !m_isSystemEntityEditor && !isLevelLayout);
+        m_gui->m_statusComboBox->setVisible(hasEntitiesDisplayed && !m_isSystemEntityEditor && !isLevelLayout);
+        m_gui->m_entityIdLabel->setVisible(hasEntitiesDisplayed && !m_isSystemEntityEditor && !isLevelLayout);
+        m_gui->m_entityIdText->setVisible(hasEntitiesDisplayed && !m_isSystemEntityEditor && !isLevelLayout);
 
         bool displayComponentSearchBox = hasEntitiesDisplayed;
         if (hasEntitiesDisplayed)
@@ -941,7 +978,7 @@ namespace AzToolsFramework
             UpdateEntityDisplay();
         }
 
-        m_gui->m_darkBox->setVisible(displayComponentSearchBox && !m_isSystemEntityEditor && !m_isLevelEntityEditor);
+        m_gui->m_darkBox->setVisible(displayComponentSearchBox && !m_isSystemEntityEditor && !isLevelLayout);
         m_gui->m_entitySearchBox->setVisible(displayComponentSearchBox);
 
         bool displayAddComponentMenu = CanAddComponentsToSelection(selectionEntityTypeInfo);

Code/Framework/AzToolsFramework/AzToolsFramework/UI/PropertyEditor/EntityPropertyEditor.hxx

@@ -32,7 +32,7 @@
 #include <AzToolsFramework/Entity/EditorEntityContextBus.h>
 #include <AzToolsFramework/ToolsComponents/ComponentMimeData.h>
 #include <AzToolsFramework/ToolsComponents/EditorInspectorComponentBus.h>
-#include <AzQtComponents/Components/LumberyardStylesheet.h>
+#include <AzQtComponents/Components/O3DEStylesheet.h>
 
 #include <QtWidgets/QWidget>
 #include <QtGui/QIcon>
@@ -521,6 +521,15 @@ namespace AzToolsFramework
         bool m_isSystemEntityEditor;
         bool m_isLevelEntityEditor = false;
 
+        enum class InspectorLayout
+        {
+            ENTITY = 0,     // All selected entities are regular entities
+            LEVEL,          // The selected entity is the level prefab container entity
+            INVALID         // Other entities are selected alongside the level prefab container entity
+        };
+
+        InspectorLayout GetCurrentInspectorLayout() const;
+
         // the spacer's job is to make sure that its always at the end of the list of components.
         QSpacerItem* m_spacer;
         bool m_isAlreadyQueuedRefresh;

Code/Framework/AzToolsFramework/AzToolsFramework/UI/PropertyEditor/PropertyAssetCtrl.cpp

@@ -38,6 +38,7 @@ AZ_POP_DISABLE_WARNING
 #include <AzCore/Asset/AssetManager.h>
 #include <AzCore/Component/ComponentApplicationBus.h>
 #include <AzCore/Asset/AssetTypeInfoBus.h>
+#include <AzCore/Utils/Utils.h>
 #include <AzFramework/StringFunc/StringFunc.h>
 #include <AzFramework/Asset/SimpleAsset.h>
 #include <AzFramework/Asset/AssetCatalogBus.h>
@@ -62,6 +63,7 @@ AZ_POP_DISABLE_WARNING
 
 #include <UI/PropertyEditor/Model/AssetCompleterModel.h>
 #include <UI/PropertyEditor/View/AssetCompleterListView.h>
+#include <UI/PropertyEditor/ThumbnailDropDown.h>
 
 namespace AzToolsFramework
 {
@@ -95,6 +97,12 @@ namespace AzToolsFramework
         m_thumbnail->setFixedSize(QSize(24, 24));
         m_thumbnail->setVisible(false);
 
+        m_thumbnailDropDown = new ThumbnailDropDown(this);
+        m_thumbnailDropDown->setFixedSize(QSize(40, 24));
+        m_thumbnailDropDown->setVisible(false);
+
+        connect(m_thumbnailDropDown, &ThumbnailDropDown::clicked, this, &PropertyAssetCtrl::OnEditButtonClicked);
+
         m_editButton = new QToolButton(this);
         m_editButton->setAutoRaise(true);
         m_editButton->setIcon(QIcon(":/stylesheet/img/UI20/open-in-internal-app.svg"));
@@ -104,6 +112,7 @@ namespace AzToolsFramework
         connect(m_editButton, &QToolButton::clicked, this, &PropertyAssetCtrl::OnEditButtonClicked);
 
         pLayout->addWidget(m_thumbnail);
+        pLayout->addWidget(m_thumbnailDropDown);
         pLayout->addWidget(m_browseEdit);
         pLayout->addWidget(m_editButton);
 
@@ -1082,8 +1091,9 @@ namespace AzToolsFramework
     void PropertyAssetCtrl::UpdateThumbnail()
     {
         m_thumbnail->setVisible(m_showThumbnail);
+        m_thumbnailDropDown->setVisible(m_showThumbnailDropDown);
 
-        if (m_showThumbnail)
+        if (m_showThumbnail || m_showThumbnailDropDown)
         {
             const AZ::Data::AssetId assetID = GetCurrentAssetID();
             if (assetID.IsValid())
@@ -1098,13 +1108,21 @@ namespace AzToolsFramework
                 if (result)
                 {
                     SharedThumbnailKey thumbnailKey = MAKE_TKEY(AzToolsFramework::AssetBrowser::ProductThumbnailKey, assetID);
-                    m_thumbnail->SetThumbnailKey(thumbnailKey, Thumbnailer::ThumbnailContext::DefaultContext);
+                    if (m_showThumbnail)
+                    {
+                        m_thumbnail->SetThumbnailKey(thumbnailKey, Thumbnailer::ThumbnailContext::DefaultContext);
+                    }
+                    if (m_showThumbnailDropDown)
+                    {
+                        m_thumbnailDropDown->SetThumbnailKey(thumbnailKey, Thumbnailer::ThumbnailContext::DefaultContext);
+                    }
                     return;
                 }
             }
         }
 
         m_thumbnail->ClearThumbnail();
+        m_thumbnailDropDown->ClearThumbnail();
     }
 
     void PropertyAssetCtrl::SetClearButtonEnabled(bool enable)
@@ -1138,6 +1156,16 @@ namespace AzToolsFramework
         return m_showThumbnail;
     }
 
+    void PropertyAssetCtrl::SetShowThumbnailDropDown(bool enable)
+    {
+        m_showThumbnailDropDown = enable;
+    }
+
+    bool PropertyAssetCtrl::GetShowThumbnailDropDown() const
+    {
+        return m_showThumbnailDropDown;
+    }
+
     const AZ::Uuid& AssetPropertyHandlerDefault::GetHandledType() const
     {
         return AZ::GetAssetClassId();
@@ -1185,9 +1213,8 @@ namespace AzToolsFramework
 
                 if (!QFile::exists(path))
                 {
-                    const char* engineRoot = nullptr;
-                    AzToolsFramework::ToolsApplicationRequestBus::BroadcastResult(engineRoot, &AzToolsFramework::ToolsApplicationRequests::GetEngineRootPath);
-                    QDir engineDir = engineRoot ? QDir(engineRoot) : QDir::current();
+                    AZ::IO::FixedMaxPathString engineRoot = AZ::Utils::GetEnginePath();
+                    QDir engineDir = !engineRoot.empty() ? QDir(QString(engineRoot.c_str())) : QDir::current();
 
                     path = engineDir.absoluteFilePath(iconPath.c_str());
                 }
@@ -1248,7 +1275,7 @@ namespace AzToolsFramework
                 GUI->SetBrowseButtonIcon(QIcon(iconPath.c_str()));
             }
         }
-        else if (attrib == AZ_CRC_CE("ShowThumbnail"))
+        else if (attrib == AZ_CRC_CE("Thumbnail"))
         {
             bool showThumbnail = false;
             if (attrValue->Read<bool>(showThumbnail))
@@ -1256,6 +1283,19 @@ namespace AzToolsFramework
                 GUI->SetShowThumbnail(showThumbnail);
             }
         }
+        else if (attrib == AZ_CRC_CE("ThumbnailWithDropDown"))
+        {
+            PropertyAssetCtrl::EditCallbackType* func = azdynamic_cast<PropertyAssetCtrl::EditCallbackType*>(attrValue->GetAttribute());
+            if (func)
+            {
+                GUI->SetShowThumbnailDropDown(true);
+                GUI->SetEditNotifyCallback(func);
+            }
+            else
+            {
+                GUI->SetEditNotifyCallback(nullptr);
+            }
+        }
     }
 
     void AssetPropertyHandlerDefault::WriteGUIValuesIntoProperty(size_t index, PropertyAssetCtrl* GUI, property_t& instance, InstanceDataNode* node)

Code/Framework/AzToolsFramework/AzToolsFramework/UI/PropertyEditor/PropertyAssetCtrl.hxx

@@ -45,6 +45,7 @@ namespace AzToolsFramework
 {
     class AssetCompleterModel;
     class AssetCompleterListView;
+    class ThumbnailDropDown;
 
     namespace Thumbnailer
     {
@@ -94,6 +95,7 @@ namespace AzToolsFramework
         void OnAssetIDChanged(AZ::Data::AssetId newAssetID);
 
     protected:
+        ThumbnailDropDown* m_thumbnailDropDown = nullptr;
         Thumbnailer::ThumbnailWidget* m_thumbnail = nullptr;
         QPushButton* m_errorButton = nullptr;
         QToolButton* m_editButton = nullptr;
@@ -156,6 +158,8 @@ namespace AzToolsFramework
 
         bool m_showThumbnail = false;
 
+        bool m_showThumbnailDropDown = false;
+
         // ! Default suffix used in the field's placeholder text when a default value is set.
         const char* m_DefaultSuffix = " (default)";
 
@@ -205,6 +209,8 @@ namespace AzToolsFramework
 
         void SetShowThumbnail(bool enable);
         bool GetShowThumbnail() const;
+        void SetShowThumbnailDropDown(bool enable);
+        bool GetShowThumbnailDropDown() const;
 
         void SetSelectedAssetID(const AZ::Data::AssetId& newID);
         void SetCurrentAssetType(const AZ::Data::AssetType& newType);

Code/Framework/AzToolsFramework/AzToolsFramework/UI/PropertyEditor/ReflectedPropertyEditor.hxx

@@ -89,7 +89,7 @@ namespace AzToolsFramework
         //! When set, disables data access for this property editor.
         //! This prevents any value refreshes from the inspected values from occurring as well as disabling user input.
         void PreventDataAccess(bool shouldPrevent);
-        // LUMBERYARD_DEPRECATED(LY-120821)
+        // O3DE_DEPRECATED(LY-120821)
         void PreventRefresh(bool shouldPrevent){PreventDataAccess(shouldPrevent);}
 
         void SetAutoResizeLabels(bool autoResizeLabels);

Code/Framework/AzToolsFramework/AzToolsFramework/UI/PropertyEditor/ThumbnailDropDown.cpp

@@ -0,0 +1,101 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include <AzToolsFramework/Debug/TraceContext.h>
+AZ_PUSH_DISABLE_WARNING(4251 4800, "-Wunknown-warning-option") // 4251: 'QRawFont::d': class 'QExplicitlySharedDataPointer<QRawFontPrivate>' needs to have dll-interface to be used by clients of class 'QRawFont'
+                                                               // 4800: 'QTextEngine *const ': forcing value to bool 'true' or 'false' (performance warning)
+#include <QLabel>
+#include <QHBoxLayout>
+#include <QEvent>
+#include <QPainter>
+#include <UI/UICore/AspectRatioAwarePixmapWidget.hxx>
+#include <Thumbnails/ThumbnailWidget.h>
+AZ_POP_DISABLE_WARNING
+#include "ThumbnailDropDown.h"
+
+namespace AzToolsFramework
+{
+    ThumbnailDropDown::ThumbnailDropDown(QWidget* parent)
+        : QWidget(parent)
+    {
+        QHBoxLayout* pLayout = new QHBoxLayout();
+        pLayout->setContentsMargins(0, 0, 0, 0);
+        pLayout->setSpacing(0);
+
+        m_thumbnail = new Thumbnailer::ThumbnailWidget(this);
+        m_thumbnail->setFixedSize(QSize(24, 24));
+
+        m_dropDownArrow = new AspectRatioAwarePixmapWidget(this);
+        m_dropDownArrow->setPixmap(QPixmap(":/stylesheet/img/triangle0.png"));
+        m_dropDownArrow->setFixedSize(QSize(8, 24));
+
+        m_emptyThumbnail = new QLabel(this);
+        m_emptyThumbnail->setPixmap(QPixmap(":/stylesheet/img/line.png"));
+        m_emptyThumbnail->setFixedSize(QSize(24, 24));
+
+        pLayout->addWidget(m_emptyThumbnail);
+        pLayout->addWidget(m_thumbnail);
+        pLayout->addSpacing(4);
+        pLayout->addWidget(m_dropDownArrow);
+        pLayout->addSpacing(4);
+
+        setLayout(pLayout);
+    }
+
+    void ThumbnailDropDown::SetThumbnailKey(Thumbnailer::SharedThumbnailKey key, const char* contextName)
+    {
+        m_emptyThumbnail->setVisible(false);
+        m_thumbnail->SetThumbnailKey(key, contextName);
+    }
+
+    void ThumbnailDropDown::ClearThumbnail()
+    {
+        m_emptyThumbnail->setVisible(true);
+        m_thumbnail->ClearThumbnail();
+    }
+
+    bool ThumbnailDropDown::event(QEvent* e)
+    {
+        if (isEnabled())
+        {
+            if (e->type() == QEvent::MouseButtonPress)
+            {
+                emit clicked();
+                return true; //ignore
+            }
+        }
+
+        return QWidget::event(e);
+    }
+
+    void ThumbnailDropDown::paintEvent(QPaintEvent* e)
+    {
+        QPainter p(this);
+        QRect targetRect(QPoint(), QSize(40, 24));
+        p.fillRect(targetRect, QColor(17, 17, 17)); // #111111
+        QWidget::paintEvent(e);
+    }
+
+    void ThumbnailDropDown::enterEvent(QEvent* e)
+    {
+        m_dropDownArrow->setPixmap(QPixmap(":/stylesheet/img/triangle0_highlighted.png"));
+        QWidget::enterEvent(e);
+    }
+
+    void ThumbnailDropDown::leaveEvent(QEvent* e)
+    {
+        m_dropDownArrow->setPixmap(QPixmap(":/stylesheet/img/triangle0.png"));
+        QWidget::leaveEvent(e);
+    }
+}
+
+#include "UI/PropertyEditor/moc_ThumbnailDropDown.cpp"

Code/Framework/AzToolsFramework/AzToolsFramework/UI/PropertyEditor/ThumbnailDropDown.h

@@ -0,0 +1,59 @@
+#pragma once
+
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#if !defined(Q_MOC_RUN)
+#include <AzCore/PlatformDef.h>
+#include <AzToolsFramework/Thumbnails/Thumbnail.h>
+AZ_PUSH_DISABLE_WARNING(4251 4800, "-Wunknown-warning-option") // 4251: class '...' needs to have dll-interface to be used by clients of class '...'
+                                                               // 4800: 'uint': forcing value to bool 'true' or 'false' (performance warning)
+#include <QWidget>
+AZ_POP_DISABLE_WARNING
+#endif
+
+namespace AzToolsFramework
+{
+    class AspectRatioAwarePixmapWidget;
+
+    namespace Thumbnailer
+    {
+        class ThumbnailWidget;
+    }
+
+    class ThumbnailDropDown : public QWidget
+    {
+        Q_OBJECT
+    public:
+        explicit ThumbnailDropDown(QWidget* parent = nullptr);
+
+        //! Call this to set what thumbnail widget will display
+        void SetThumbnailKey(Thumbnailer::SharedThumbnailKey key, const char* contextName = "Default");
+        //! Remove current thumbnail
+        void ClearThumbnail();
+
+        bool event(QEvent* e) override;
+
+    Q_SIGNALS:
+        void clicked();
+
+    protected:
+        void paintEvent(QPaintEvent* e) override;
+        void enterEvent(QEvent* e) override;
+        void leaveEvent(QEvent* e) override;
+
+    private:
+        Thumbnailer::ThumbnailWidget* m_thumbnail = nullptr;
+        QLabel* m_emptyThumbnail = nullptr;
+        AspectRatioAwarePixmapWidget* m_dropDownArrow = nullptr;
+    };
+}

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Slice/SliceOverridesNotificationWindow.cpp

@@ -11,7 +11,7 @@
 */
 #include "AzToolsFramework_precompiled.h"
 AZ_PUSH_DISABLE_WARNING(4251, "-Wunknown-warning-option") // 4251: 'QLayoutItem::align': class 'QFlags<Qt::AlignmentFlag>' needs to have dll-interface to be used by clients of class 'QLayoutItem'
-#include "UI/Slice/ui_NotificationWindow.h"
+#include <AzToolsFramework/UI/Slice/ui_NotificationWindow.h>
 AZ_POP_DISABLE_WARNING
 #include "UI/Slice/Constants.h"
 

Code/Framework/AzToolsFramework/AzToolsFramework/UI/UICore/OverwritePromptDialog.cpp

@@ -14,7 +14,7 @@
 #include "OverwritePromptDialog.hxx"
 
 AZ_PUSH_DISABLE_WARNING(4251, "-Wunknown-warning-option") // 'QLayoutItem::align': class 'QFlags<Qt::AlignmentFlag>' needs to have dll-interface to be used by clients of class 'QLayoutItem'
-#include <UI/UICore/ui_OverwritePromptDialog.h>
+#include <AzToolsFramework/UI/UICore/ui_OverwritePromptDialog.h>
 AZ_POP_DISABLE_WARNING
 
 namespace AzToolsFramework
@@ -54,4 +54,4 @@ namespace AzToolsFramework
 
 }
 
-#include "UI/UICore/moc_OverwritePromptDialog.cpp"
+#include "UI/UICore/moc_OverwritePromptDialog.cpp"

Code/Framework/AzToolsFramework/AzToolsFramework/UI/UICore/ProgressShield.cpp

@@ -18,7 +18,7 @@
 #include <AzToolsFramework/UI/UICore/ProgressShield.hxx>
 
 AZ_PUSH_DISABLE_WARNING(4251, "-Wunknown-warning-option") // 4251: 'QLayoutItem::align': class 'QFlags<Qt::AlignmentFlag>' needs to have dll-interface to be used by clients of class 'QLayoutItem'
-#include <UI/UICore/ui_ProgressShield.h>
+#include <AzToolsFramework/UI/UICore/ui_ProgressShield.h>
 AZ_POP_DISABLE_WARNING
 
 namespace AzToolsFramework
@@ -118,4 +118,4 @@ namespace AzToolsFramework
 
 } // namespace AzToolsFramework
 
-#include "UI/UICore/moc_ProgressShield.cpp"
+#include "UI/UICore/moc_ProgressShield.cpp"

Code/Framework/AzToolsFramework/AzToolsFramework/UI/UICore/SaveChangesDialog.cpp

@@ -14,7 +14,7 @@
 #include "SaveChangesDialog.hxx"
 
 AZ_PUSH_DISABLE_WARNING(4244 4251, "-Wunknown-warning-option")
-#include <UI/UICore/ui_SaveChangesDialog.h>
+#include <AzToolsFramework/UI/UICore/ui_SaveChangesDialog.h>
 AZ_POP_DISABLE_WARNING
 
 namespace AzToolsFramework
@@ -52,4 +52,4 @@ namespace AzToolsFramework
     }
 }
 
-#include "UI/UICore/moc_SaveChangesDialog.cpp"
+#include "UI/UICore/moc_SaveChangesDialog.cpp"

Code/Framework/AzToolsFramework/AzToolsFramework/UnitTest/AzToolsFrameworkTestHelpers.cpp

@@ -246,7 +246,7 @@ namespace UnitTest
                 R"(... client unittest_workspace)" "\r\n"
                 R"(... status pending)" "\r\n"
                 R"(... changeType public)" "\r\n"
-                R"(... desc *Lumberyard Auto)" "\r\n"
+                R"(... desc *Open 3D Engine Auto)" "\r\n"
                 "\r\n";
         }
         else if (m_commandArgs.starts_with("fstat"))

Code/Framework/AzToolsFramework/AzToolsFramework/Viewport/EditorContextMenu.cpp

@@ -65,7 +65,7 @@ namespace AzToolsFramework
 
                 if (!contextMenu.m_menu->isEmpty())
                 {
-                    contextMenu.m_menu->popup(QCursor::pos());
+                    contextMenu.m_menu->exec(QCursor::pos());
                 }
             }
         }

Code/Framework/AzToolsFramework/AzToolsFramework/Viewport/ViewportMessages.h

@@ -21,7 +21,12 @@
 #include <AzToolsFramework/Entity/EditorEntityContextBus.h>
 #include <AzToolsFramework/Viewport/ViewportTypes.h>
 
-class QPoint;
+class QPoint; // LYN-2315 in-progress, remove this
+
+namespace AzFramework
+{
+    struct ScreenPoint;
+}
 
 namespace AzToolsFramework
 {
@@ -235,12 +240,12 @@ namespace AzToolsFramework
             /// Restores the cursor and ends locking it in place, allowing it to be moved freely.
             virtual void EndCursorCapture() = 0;
             /// Gets the most recent recorded cursor position in the viewport in screen space coordinates.
-            virtual QPoint ViewportCursorScreenPosition() = 0;
+            virtual AzFramework::ScreenPoint ViewportCursorScreenPosition() = 0;
             /// Gets the cursor position recorded prior to the most recent cursor position.
             /// Note: The cursor may be captured by the viewport, in which case this may not correspond to the last result
             /// from ViewportCursorScreenPosition. This method will always return the correct position to generate a mouse
             /// position delta.
-            virtual AZStd::optional<QPoint> PreviousViewportCursorScreenPosition() = 0;
+            virtual AZStd::optional<AzFramework::ScreenPoint> PreviousViewportCursorScreenPosition() = 0;
 
         protected:
             ~ViewportMouseCursorRequests() = default;

Code/Framework/AzToolsFramework/AzToolsFramework/Viewport/ViewportTypes.h

@@ -202,13 +202,19 @@ namespace AzToolsFramework
             return mouseInteractionEvent.m_wheelDelta;
         }
 
-        /// Return Qt QPoint from an Viewport ScreenPoint.
+        /// Return QPoint from AzFramework::ScreenPoint.
         inline QPoint QPointFromScreenPoint(const AzFramework::ScreenPoint& screenPoint)
         {
             return {screenPoint.m_x, screenPoint.m_y};
         }
 
-        /// Map from Qt -> Lumberyard buttons.
+        /// Return AzFramework::ScreenPoint from QPoint.
+        inline AzFramework::ScreenPoint ScreenPointFromQPoint(const QPoint& qpoint)
+        {
+            return AzFramework::ScreenPoint{qpoint.x(), qpoint.y()};
+        }
+
+        /// Map from Qt -> Open 3D Engine buttons.>>>>>>> main
         inline AZ::u32 TranslateMouseButtons(const Qt::MouseButtons buttons)
         {
             AZ::u32 result = 0;
@@ -218,7 +224,7 @@ namespace AzToolsFramework
             return result;
         }
 
-        /// Map from Qt -> Lumberyard modifiers.
+        /// Map from Qt -> Open 3D Engine modifiers.
         inline AZ::u32 TranslateKeyboardModifiers(const Qt::KeyboardModifiers modifiers)
         {
             AZ::u32 result = 0;
@@ -228,13 +234,13 @@ namespace AzToolsFramework
             return result;
         }
 
-        /// Interface to translate Qt modifiers to Lumberyard modifiers.
+        /// Interface to translate Qt modifiers to Open 3D Engine modifiers.
         inline KeyboardModifiers BuildKeyboardModifiers(const Qt::KeyboardModifiers modifiers)
         {
             return KeyboardModifiers(TranslateKeyboardModifiers(modifiers));
         }
 
-        /// Interface to translate Qt buttons to Lumberyard buttons.
+        /// Interface to translate Qt buttons to Open 3D Engine buttons.
         inline MouseButtons BuildMouseButtons(const Qt::MouseButtons buttons)
         {
             return MouseButtons(TranslateMouseButtons(buttons));

Code/Framework/AzToolsFramework/AzToolsFramework/ViewportSelection/EditorTransformComponentSelection.cpp

@@ -53,7 +53,7 @@ namespace AzToolsFramework
         float, cl_viewportGizmoAxisLabelOffset, 1.15f, nullptr, AZ::ConsoleFunctorFlags::Null,
         "The offset of the label for the viewport axis gizmo");
     AZ_CVAR(
-        float, cl_viewportGizmoAxisLabelSize, 2.0f, nullptr, AZ::ConsoleFunctorFlags::Null,
+        float, cl_viewportGizmoAxisLabelSize, 1.0f, nullptr, AZ::ConsoleFunctorFlags::Null,
         "The size of each label for the viewport axis gizmo");
     AZ_CVAR(
         AZ::Vector2, cl_viewportGizmoAxisScreenPosition, AZ::Vector2(0.045f, 0.9f), nullptr,
@@ -1626,7 +1626,7 @@ namespace AzToolsFramework
 
                 const AZ::Vector3 uniformScale = AZ::Vector3(action.m_start.m_sign * sumVectorElements(action.LocalScaleOffset()));
                 const AZ::Vector3 scale = (AZ::Vector3::CreateOne() +
-                    (uniformScale / initialScale)).GetMax(AZ::Vector3(0.01f));
+                    (uniformScale / initialScale)).GetClamp(AZ::Vector3(AZ::MinTransformScale), AZ::Vector3(AZ::MaxTransformScale));
                 const AZ::Transform scaleTransform = AZ::Transform::CreateScale(scale);
 
                 if (action.m_modifiers.Alt())
@@ -3501,19 +3501,22 @@ namespace AzToolsFramework
         const auto cameraProjection = AzFramework::CameraProjection(gizmoCameraState);
 
         // screen space offset to move the 2d gizmo around
-        const AZ::Vector3 screenPosition =
-            (AZ::Vector2ToVector3(cl_viewportGizmoAxisScreenPosition) - AZ::Vector3(0.5f, 0.5f, 0.0f)) *
-            AZ::Vector2ToVector3(gizmoCameraState.m_viewportSize);
+        const AZ::Vector2 screenOffset = AZ::Vector2(cl_viewportGizmoAxisScreenPosition) - AZ::Vector2(0.5f, 0.5f);
 
         // map from a position in world space (relative to the the gizmo camera near the origin) to a position in
         // screen space
         const auto calculateGizmoAxis =
-            [&cameraView, &cameraProjection, &gizmoCameraState, &screenPosition]
-            (const AZ::Vector3& position)
+            [&cameraView, &cameraProjection, &screenOffset]
+            (const AZ::Vector3& axis)
         {
-            return AZ::Vector2ToVector3(AzFramework::Vector2FromScreenPoint(
-                AzFramework::WorldToScreen(
-                    position, cameraView, cameraProjection, gizmoCameraState.m_viewportSize))) + screenPosition;
+            auto result = AZ::Vector2(
+                AzFramework::WorldToScreenNDC(
+                    axis,
+                    cameraView,
+                    cameraProjection)
+            );
+            result.SetY(1.0f - result.GetY());
+            return result + screenOffset;
         };
 
         // get all important axis positions in screen space
@@ -3523,31 +3526,31 @@ namespace AzToolsFramework
         const auto gizmoEndAxisY = calculateGizmoAxis(-AZ::Vector3::CreateAxisY() * lineLength);
         const auto gizmoEndAxisZ = calculateGizmoAxis(-AZ::Vector3::CreateAxisZ() * lineLength);
 
-        const AZ::Vector3 gizmoAxisX = gizmoEndAxisX - gizmoStart;
-        const AZ::Vector3 gizmoAxisY = gizmoEndAxisY - gizmoStart;
-        const AZ::Vector3 gizmoAxisZ = gizmoEndAxisZ - gizmoStart;
+        const AZ::Vector2 gizmoAxisX = gizmoEndAxisX - gizmoStart;
+        const AZ::Vector2 gizmoAxisY = gizmoEndAxisY - gizmoStart;
+        const AZ::Vector2 gizmoAxisZ = gizmoEndAxisZ - gizmoStart;                                          
 
         // draw the axes of the gizmo
         debugDisplay.SetLineWidth(cl_viewportGizmoAxisLineWidth);
         debugDisplay.SetColor(AZ::Colors::Red);
-        debugDisplay.DrawLine(gizmoStart, gizmoEndAxisX);
+        debugDisplay.DrawLine2d(gizmoStart, gizmoEndAxisX, 1.0f);
         debugDisplay.SetColor(AZ::Colors::Lime);
-        debugDisplay.DrawLine(gizmoStart, gizmoEndAxisY);
+        debugDisplay.DrawLine2d(gizmoStart, gizmoEndAxisY, 1.0f);
         debugDisplay.SetColor(AZ::Colors::Blue);
-        debugDisplay.DrawLine(gizmoStart, gizmoEndAxisZ);
+        debugDisplay.DrawLine2d(gizmoStart, gizmoEndAxisZ, 1.0f);
         debugDisplay.SetLineWidth(1.0f);
 
         const float labelOffset = cl_viewportGizmoAxisLabelOffset;
-        const auto labelOffsetX = gizmoStart + gizmoAxisX * labelOffset;
-        const auto labelOffsetY = gizmoStart + gizmoAxisY * labelOffset;
-        const auto labelOffsetZ = gizmoStart + gizmoAxisZ * labelOffset;
+        const auto labelXScreenPosition = (gizmoStart + (gizmoAxisX * labelOffset)) * editorCameraState.m_viewportSize;
+        const auto labelYScreenPosition = (gizmoStart + (gizmoAxisY * labelOffset)) * editorCameraState.m_viewportSize;
+        const auto labelZScreenPosition = (gizmoStart + (gizmoAxisZ * labelOffset)) * editorCameraState.m_viewportSize;
 
         // draw the label of of each axis for the gizmo
         const float labelSize = cl_viewportGizmoAxisLabelSize;
         debugDisplay.SetColor(AZ::Colors::White);
-        debugDisplay.Draw2dTextLabel(labelOffsetX.GetX(), labelOffsetX.GetY(), labelSize, "X", true);
-        debugDisplay.Draw2dTextLabel(labelOffsetY.GetX(), labelOffsetY.GetY(), labelSize, "Y", true);
-        debugDisplay.Draw2dTextLabel(labelOffsetZ.GetX(), labelOffsetZ.GetY(), labelSize, "Z", true);
+        debugDisplay.Draw2dTextLabel(labelXScreenPosition.GetX(), labelXScreenPosition.GetY(), labelSize, "X", true);
+        debugDisplay.Draw2dTextLabel(labelYScreenPosition.GetX(), labelYScreenPosition.GetY(), labelSize, "Y", true);
+        debugDisplay.Draw2dTextLabel(labelZScreenPosition.GetX(), labelZScreenPosition.GetY(), labelSize, "Z", true);
     }
 
     void EditorTransformComponentSelection::DisplayViewportSelection2d(

Code/Framework/AzToolsFramework/AzToolsFramework/aztoolsframework_files.cmake

@@ -417,6 +417,8 @@ set(FILES
     UI/PropertyEditor/GrowTextEdit.cpp
     UI/PropertyEditor/MultiLineTextEditHandler.h
     UI/PropertyEditor/MultiLineTextEditHandler.cpp
+    UI/PropertyEditor/ThumbnailDropDown.h
+    UI/PropertyEditor/ThumbnailDropDown.cpp
     UI/Slice/SlicePushWidget.cpp
     UI/Slice/SlicePushWidget.hxx
     UI/Slice/SliceOverridesNotificationWindow.cpp
@@ -649,6 +651,15 @@ set(FILES
     Prefab/Instance/TemplateInstanceMapperInterface.h
     Prefab/Link/Link.h
     Prefab/Link/Link.cpp
+    Prefab/PrefabPublicHandler.h
+    Prefab/PrefabPublicHandler.cpp
+    Prefab/PrefabPublicInterface.h
+    Prefab/PrefabUndo.h
+    Prefab/PrefabUndo.cpp
+    Prefab/PrefabUndoCache.cpp
+    Prefab/PrefabUndoCache.h
+    Prefab/PrefabUndoHelpers.cpp
+    Prefab/PrefabUndoHelpers.h
     Prefab/Spawnable/ComponentRequirementsValidator.h
     Prefab/Spawnable/ComponentRequirementsValidator.cpp
     Prefab/Spawnable/EditorInfoRemover.h
@@ -674,13 +685,6 @@ set(FILES
     Prefab/Spawnable/SpawnableUtils.cpp
     Prefab/Template/Template.h
     Prefab/Template/Template.cpp
-    Prefab/PrefabUndo.h
-    Prefab/PrefabUndo.cpp
-    Prefab/PrefabUndoCache.cpp
-    Prefab/PrefabUndoCache.h
-    Prefab/PrefabPublicHandler.h
-    Prefab/PrefabPublicHandler.cpp
-    Prefab/PrefabPublicInterface.h
     UI/Outliner/EntityOutlinerDisplayOptionsMenu.h
     UI/Outliner/EntityOutlinerDisplayOptionsMenu.cpp
     UI/Outliner/EntityOutlinerTreeView.hxx
@@ -705,6 +709,8 @@ set(FILES
     UI/EditorEntityUi/EditorEntityUiSystemComponent.cpp
     UI/Layer/LayerUiHandler.h
     UI/Layer/LayerUiHandler.cpp
+    UI/Prefab/LevelRootUiHandler.h
+    UI/Prefab/LevelRootUiHandler.cpp
     UI/Prefab/PrefabEditInterface.h
     UI/Prefab/PrefabEditManager.h
     UI/Prefab/PrefabEditManager.cpp