Address a few more review things

Signed-off-by: nvsickle <nvsickle@amazon.com>

Code/Framework/AzToolsFramework/AzToolsFramework/Input/QtEventToAzInputManager.cpp

@@ -200,8 +200,24 @@ namespace AzToolsFramework
             deviceId.GetNameCrc32() == AzFramework::InputDeviceKeyboard::Id.GetNameCrc32();
     }
 
+    void QtEventToAzInputMapper::SetEnabled(bool enabled)
+    {
+        m_enabled = enabled;
+        if (!enabled)
+        {
+            // Send an internal focus change event to reset our input state to fresh if we're disabled.
+            HandleFocusChange(nullptr);
+        }
+    }
+
     bool QtEventToAzInputMapper::eventFilter(QObject* object, QEvent* event)
     {
+        // Abort if processing isn't enabled.
+        if (!m_enabled)
+        {
+            return false;
+        }
+
         // Because there's no "end" to mouse movement and wheel events, we reset mouse movement channels that have been opened
         // during the next processed non-mouse event.
         if (m_mouseChannelsNeedUpdate && event->type() != QEvent::Type::MouseMove && event->type() != QEvent::Type::Wheel)
@@ -268,14 +284,14 @@ namespace AzToolsFramework
     {
         auto systemCursorChannel =
             GetInputChannel<AzFramework::InputChannelDeltaWithSharedPosition2D>(AzFramework::InputDeviceMouse::SystemCursorPosition);
-        auto cursorZChannel =
+        auto mouseWheelChannel =
             GetInputChannel<AzFramework::InputChannelDeltaWithSharedPosition2D>(AzFramework::InputDeviceMouse::Movement::Z);
 
         systemCursorChannel->ProcessRawInputEvent(m_cursorPosition->m_normalizedPositionDelta.GetLength());
-        cursorZChannel->ProcessRawInputEvent(0.f);
+        mouseWheelChannel->ProcessRawInputEvent(0.f);
 
         NotifyUpdateChannelIfNotIdle(systemCursorChannel, nullptr);
-        NotifyUpdateChannelIfNotIdle(cursorZChannel, nullptr);
+        NotifyUpdateChannelIfNotIdle(mouseWheelChannel, nullptr);
     }
 
     void QtEventToAzInputMapper::HandleMouseButtonEvent(QMouseEvent* mouseEvent)

Code/Framework/AzToolsFramework/AzToolsFramework/Input/QtEventToAzInputManager.h

@@ -44,6 +44,9 @@ namespace AzToolsFramework
         //! \returns true if the channel is handled by MapQtEventToAzInput.
         bool HandlesInputEvent(const AzFramework::InputChannel& channel) const;
 
+        //! Sets whether or not this input mapper should be updating its input channels from Qt events.
+        void SetEnabled(bool enabled);
+
         // QObject overrides...
         bool eventFilter(QObject* object, QEvent* event) override;
 
@@ -64,7 +67,7 @@ namespace AzToolsFramework
             {
                 return static_cast<TInputChannel*>(channelIt->second);
             }
-            return {};
+            return nullptr;
         }
 
         // Adds channels from the specified channel container to our input channel ID -> input channel lookup table.
@@ -139,6 +142,8 @@ namespace AzToolsFramework
         QWidget* m_sourceWidget;
         // Flags when mouse movement channels have been opened and may need to be closed (as there are no movement ended events).
         bool m_mouseChannelsNeedUpdate = false;
+        // Flags whether or not Qt events should currently be processed.
+        bool m_enabled = true;
 
         // Our viewport-specific AZ devices. We control their internal input channel states.
         AZStd::unique_ptr<EditorQtMouseDevice> m_mouseDevice;