diff --git a/editor/idl/nsIHTMLObjectResizer.idl b/editor/idl/nsIHTMLObjectResizer.idl
index 90b53ecc6e4..9774b6da1e3 100644
--- a/editor/idl/nsIHTMLObjectResizer.idl
+++ b/editor/idl/nsIHTMLObjectResizer.idl
@@ -41,7 +41,7 @@
 
 interface nsIHTMLObjectResizeListener;
 
-[scriptable, uuid(b0338f6c-ded3-4c39-a953-56e8bae494f5)]
+[scriptable, uuid(8b396020-69d3-451f-80c1-1a96a7da25a9)]
 
 interface nsIHTMLObjectResizer : nsISupports
 {
@@ -88,9 +88,10 @@ interface nsIHTMLObjectResizer : nsISupports
    * @param aX      [IN] horizontal position of the pointer
    * @param aY      [IN] vertical position of the pointer
    * @param aTarget [IN] the element triggering the event
+   * @param aMouseEvent [IN] the event
    */
   void mouseDown(in long aX, in long aY,
-                 in nsIDOMElement aTarget);
+                 in nsIDOMElement aTarget, in nsIDOMEvent aMouseEvent);
 
   /**
    * event callback when a mouse button is released
diff --git a/editor/libeditor/html/nsHTMLEditorMouseListener.cpp b/editor/libeditor/html/nsHTMLEditorMouseListener.cpp
index 548c5c898e8..7a4e88e0b1b 100644
--- a/editor/libeditor/html/nsHTMLEditorMouseListener.cpp
+++ b/editor/libeditor/html/nsHTMLEditorMouseListener.cpp
@@ -275,7 +275,7 @@ nsHTMLEditorMouseListener::MouseDown(nsIDOMEvent* aMouseEvent)
       PRInt32 clientX, clientY;
       mouseEvent->GetClientX(&clientX);
       mouseEvent->GetClientY(&clientY);
-      objectResizer->MouseDown(clientX, clientY, element);
+      objectResizer->MouseDown(clientX, clientY, element, aMouseEvent);
     }
   }
 
diff --git a/editor/libeditor/html/nsHTMLObjectResizer.cpp b/editor/libeditor/html/nsHTMLObjectResizer.cpp
index 96d1e5ad1f7..30dd16d0da9 100644
--- a/editor/libeditor/html/nsHTMLObjectResizer.cpp
+++ b/editor/libeditor/html/nsHTMLObjectResizer.cpp
@@ -623,7 +623,7 @@ nsHTMLEditor::StartResizing(nsIDOMElement *aHandle)
 
 NS_IMETHODIMP 
 nsHTMLEditor::MouseDown(PRInt32 aClientX, PRInt32 aClientY,
-                        nsIDOMElement *aTarget)
+                        nsIDOMElement *aTarget, nsIDOMEvent* aEvent)
 {
   PRBool anonElement = PR_FALSE;
   if (aTarget && NS_SUCCEEDED(aTarget->HasAttribute(NS_LITERAL_STRING("_moz_anonclass"), &anonElement)))
@@ -634,6 +634,8 @@ nsHTMLEditor::MouseDown(PRInt32 aClientX, PRInt32 aClientY,
       if (NS_FAILED(res)) return res;
       if (anonclass.EqualsLiteral("mozResizer")) {
         // and that element is a resizer, let's start resizing!
+        aEvent->PreventDefault();
+
         mOriginalX = aClientX;
         mOriginalY = aClientY;
         return StartResizing(aTarget);