Clear references holding on to types in game assemblies

Source/Editor/CustomEditors/CustomEditorPresenter.cs

@@ -195,6 +195,15 @@ namespace FlaxEditor.CustomEditors
                 Presenter.AfterLayout?.Invoke(layout);
             }
 
+            /// <inheritdoc />
+            protected override void Deinitialize()
+            {
+                Editor = null;
+                _overrideEditor = null;
+
+                base.Deinitialize();
+            }
+
             /// <inheritdoc />
             protected override void OnModified()
             {

Source/Editor/CustomEditors/Dedicated/ScriptsEditor.cs

@@ -1057,6 +1057,7 @@ namespace FlaxEditor.CustomEditors.Dedicated
         protected override void Deinitialize()
         {
             _scriptToggles = null;
+            _scripts.Clear();
 
             base.Deinitialize();
         }

Source/Editor/CustomEditors/Editors/GenericEditor.cs

@@ -819,6 +819,14 @@ namespace FlaxEditor.CustomEditors.Editors
             OnGroupsEnd();
         }
 
+        protected override void Deinitialize()
+        {
+            _visibleIfCaches = null;
+            _visibleIfPropertiesListsCache = null;
+
+            base.Deinitialize();
+        }
+
         /// <inheritdoc />
         public override void Refresh()
         {

Source/Editor/SceneGraph/SceneGraphNode.cs

@@ -469,6 +469,7 @@ namespace FlaxEditor.SceneGraph
             {
                 ChildNodes[i].OnDispose();
             }
+            ChildNodes.Clear();
 
             SceneGraphFactory.Nodes.Remove(ID);
         }

Source/Engine/UI/GUI/Tooltip.cs

@@ -120,6 +120,7 @@ namespace FlaxEngine.GUI
             // Unlink
             IsLayoutLocked = true;
             Parent = null;
+            _showTarget = null;
 
             // Close window
             if (_window)