diff --git a/layout/xul/base/src/nsMenuFrame.cpp b/layout/xul/base/src/nsMenuFrame.cpp
index 326e3098b012..2fe3d5d64bd2 100644
--- a/layout/xul/base/src/nsMenuFrame.cpp
+++ b/layout/xul/base/src/nsMenuFrame.cpp
@@ -585,9 +585,11 @@ nsMenuFrame::OpenMenuInternal(PRBool aActivateFlag)
 
     if (menuPopup) {
       // inherit whether or not we're a context menu from the parent
-      PRBool parentIsContextMenu = PR_FALSE;
-      mMenuParent->GetIsContextMenu(parentIsContextMenu);
-      menuPopup->SetIsContextMenu(parentIsContextMenu);
+      if ( mMenuParent ) {
+        PRBool parentIsContextMenu = PR_FALSE;
+        mMenuParent->GetIsContextMenu(parentIsContextMenu);
+        menuPopup->SetIsContextMenu(parentIsContextMenu);
+      }
 
       // Install a keyboard navigation listener if we're the root of the menu chain.
       PRBool onMenuBar = PR_TRUE;