diff --git a/widget/public/nsIWidget.h b/widget/public/nsIWidget.h
index a37f84cd742..5e1bcbd42e3 100644
--- a/widget/public/nsIWidget.h
+++ b/widget/public/nsIWidget.h
@@ -1053,12 +1053,6 @@ class nsIWidget : public nsISupports {
      */
     NS_IMETHOD GetAnimatedResize(PRUint16* aAnimation) = 0;
 
-    /*
-     * Return the the nearest ancestor widget which does not have a
-     * Gecko parent.
-     */
-    virtual nsIWidget* GetTopLevelWindow(void) = 0;
-
 protected:
     // keep the list of children.  We also keep track of our siblings.
     // The ownership model is as follows: parent holds a strong ref to