diff --git a/mozilla/layout/xul/base/public/nsIMenuFrame.h b/mozilla/layout/xul/base/public/nsIMenuFrame.h
index 0108d3a771b..19a1aa4e635 100644
--- a/mozilla/layout/xul/base/public/nsIMenuFrame.h
+++ b/mozilla/layout/xul/base/public/nsIMenuFrame.h
@@ -47,6 +47,7 @@ public:
   NS_IMETHOD MenuIsOpen(PRBool& aResult) = 0;
   NS_IMETHOD MenuIsContainer(PRBool& aResult) = 0;
   NS_IMETHOD MenuIsChecked(PRBool& aResult) = 0;
+  NS_IMETHOD MenuIsDisabled(PRBool& aResult) = 0;
 
   NS_IMETHOD SelectFirstItem() = 0;