diff --git a/sources/editor/Xenko.Core.Assets.Editor/View/Behaviors/DragDrop/DragDropBehavior.cs b/sources/editor/Xenko.Core.Assets.Editor/View/Behaviors/DragDrop/DragDropBehavior.cs
index 1f6e53fa20..9eada83460 100644
--- a/sources/editor/Xenko.Core.Assets.Editor/View/Behaviors/DragDrop/DragDropBehavior.cs
+++ b/sources/editor/Xenko.Core.Assets.Editor/View/Behaviors/DragDrop/DragDropBehavior.cs
@@ -314,7 +314,7 @@ protected object InitializeDrag(object originalSource)
             }
             object data = null;
             var container = GetContainer(originalSource);
-            var itemsToDrag = GetItemsToDrag(container).Where(x => !(x is IIsEditableViewModel) || ((IIsEditableViewModel)x).IsEditable).ToList();
+            var itemsToDrag = GetItemsToDrag(container).ToList();
             if (itemsToDrag.Count > 0)
             {
                 var dragContainer = new DragContainer(itemsToDrag);
diff --git a/sources/editor/Xenko.Core.Assets.Editor/ViewModel/DirectoryBaseViewModel.cs b/sources/editor/Xenko.Core.Assets.Editor/ViewModel/DirectoryBaseViewModel.cs
index 7531c2bb1b..ac03370746 100644
--- a/sources/editor/Xenko.Core.Assets.Editor/ViewModel/DirectoryBaseViewModel.cs
+++ b/sources/editor/Xenko.Core.Assets.Editor/ViewModel/DirectoryBaseViewModel.cs
@@ -190,6 +190,12 @@ protected void UpdateAssetUrls()
 
         bool IAddChildViewModel.CanAddChildren(IReadOnlyCollection<object> children, AddChildModifiers modifiers, out string message)
         {
+            if (children.Any(x => (x is IIsEditableViewModel) && !((IIsEditableViewModel)x).IsEditable))
+            {
+                message = "Some source items are read-only";
+                return false;
+            }
+
             if (!Package.IsEditable)
             {
                 message = "Read-only package";