diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index 83bd9146a..074ba5a91 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -1297,7 +1297,7 @@ Workspace.prototype = {
 
     // Draggable target interface
     handleDragOver : function(source, actor, x, y, time) {
-        if (source instanceof WindowClone)
+        if (source.realWindow && !this._isMyWindow(source.realWindow))
             return DND.DragMotionResult.MOVE_DROP;
         if (source.shellWorkspaceLaunch)
             return DND.DragMotionResult.COPY_DROP;
diff --git a/js/ui/workspaceThumbnail.js b/js/ui/workspaceThumbnail.js
index ab9ea9091..06dec6f6d 100644
--- a/js/ui/workspaceThumbnail.js
+++ b/js/ui/workspaceThumbnail.js
@@ -343,7 +343,7 @@ WorkspaceThumbnail.prototype = {
         if (this.state > ThumbnailState.NORMAL)
             return DND.DragMotionResult.CONTINUE;
 
-        if (source.realWindow)
+        if (source.realWindow && !this._isMyWindow(source.realWindow))
             return DND.DragMotionResult.MOVE_DROP;
         if (source.shellWorkspaceLaunch)
             return DND.DragMotionResult.COPY_DROP;