diff --git a/widget/public/nsIWidget.h b/widget/public/nsIWidget.h
index 51e27fc5f41..6315e78cff8 100644
--- a/widget/public/nsIWidget.h
+++ b/widget/public/nsIWidget.h
@@ -608,6 +608,12 @@ class nsIWidget : public nsISupports {
     NS_IMETHOD DispatchEvent(nsGUIEvent* event, nsEventStatus & aStatus) = 0;
 
 
+    /**
+     * FSets the vertical scrollbar widget
+     *
+     */
+    NS_IMETHOD SetVerticalScrollbar(nsIWidget * aScrollbar) = 0;
+   
     /**
      * For printing and lightweight widgets
      *