Update to include presenter context.

Source/Editor/CustomEditors/Editors/ControlReferenceEditor.cs

@@ -4,7 +4,10 @@ using FlaxEditor.CustomEditors;
 using FlaxEditor.CustomEditors.Elements;
 using FlaxEditor.GUI;
 using FlaxEditor.GUI.Drag;
+using FlaxEditor.SceneGraph;
 using FlaxEditor.SceneGraph.GUI;
+using FlaxEditor.Windows;
+using FlaxEditor.Windows.Assets;
 using FlaxEngine;
 using FlaxEngine.GUI;
 using FlaxEngine.Utilities;
@@ -31,6 +34,11 @@ public class UIControlRefPickerControl : Control
     private DragActors _dragActors;
     private DragHandlers _dragHandlers;
     
+    /// <summary>
+    /// The presenter using this control.
+    /// </summary>
+    public IPresenterOwner PresenterContext;
+    
     /// <summary>
     /// Occurs when value gets changed.
     /// </summary>
@@ -126,7 +134,7 @@ public class UIControlRefPickerControl : Control
                 Value = actor as UIControl;
                 RootWindow.Focus();
                 Focus();
-            });
+            }, PresenterContext);
         }
     }
 
@@ -134,6 +142,24 @@ public class UIControlRefPickerControl : Control
     {
         return actor == null || actor is UIControl a && a.Control.GetType() == _controlType;
     }
+    
+    private bool ValidateDragActor(ActorNode a)
+    {
+        if (!IsValid(a.Actor))
+            return false;
+            
+        if (PresenterContext is PrefabWindow prefabWindow)
+        {
+            if (prefabWindow.Tree == a.TreeNode.ParentTree)
+                return true;
+        }
+        else if (PresenterContext is PropertiesWindow || PresenterContext == null)
+        {
+            if (a.ParentScene != null)
+                return true;
+        }
+        return false;
+    }
 
     /// <inheritdoc />
     public override void Draw()
@@ -365,7 +391,7 @@ public class UIControlRefPickerControl : Control
 
         // Ensure to have valid drag helpers (uses lazy init)
         if (_dragActors == null)
-            _dragActors = new DragActors(x => IsValid(x.Actor));
+            _dragActors = new DragActors(ValidateDragActor);
         if (_dragHandlers == null)
         {
             _dragHandlers = new DragHandlers
@@ -448,6 +474,7 @@ public class ControlReferenceEditor : CustomEditor
             Type genType = ValuesTypes[0].GetGenericArguments()[0];
             if (typeof(Control).IsAssignableFrom(genType))
             {
+                _element.CustomControl.PresenterContext = Presenter.Owner;
                 _element.CustomControl.ControlType = genType;
             }
             _element.CustomControl.ValueChanged += () =>

Source/Engine/UI/ControlReference.cs

@@ -63,7 +63,7 @@ public struct ControlReference<T> : IControlReference where T : Control
                 return t;
             else
             {
-                Debug.LogWarning("Trying to get Control from ControlReference but UIControl is null, or UIControl.Control is null, or UIControl.Control is not the correct type.");
+                Debug.Write(LogType.Warning, "Trying to get Control from ControlReference but UIControl is null, or UIControl.Control is null, or UIControl.Control is not the correct type.");
                 return null;
             }
         }
@@ -84,7 +84,7 @@ public struct ControlReference<T> : IControlReference where T : Control
         if (uiControl.Control is T castedControl)
             _uiControl = uiControl;
         else
-            Debug.LogWarning("Trying to set ControlReference but UIControl.Control is null or UIControl.Control is not the correct type.");
+            Debug.Write(LogType.Warning, "Trying to set ControlReference but UIControl.Control is null or UIControl.Control is not the correct type.");
     }
 
     /// <summary>