diff --git a/Source/Editor/Windows/SceneTreeWindow.cs b/Source/Editor/Windows/SceneTreeWindow.cs
index 601f03d53..a750a076b 100644
--- a/Source/Editor/Windows/SceneTreeWindow.cs
+++ b/Source/Editor/Windows/SceneTreeWindow.cs
@@ -443,7 +443,7 @@ namespace FlaxEditor.Windows
         public override DragDropEffect OnDragMove(ref Vector2 location, DragData data)
         {
             var result = base.OnDragMove(ref location, data);
-            if (result == DragDropEffect.None && Editor.StateMachine.CurrentState.CanEditScene)
+            if (result == DragDropEffect.None && Editor.StateMachine.CurrentState.CanEditScene && _dragHandlers != null)
             {
                 result = _dragHandlers.Effect;
             }