Fix context menu keyboard shortcut on Mac. Bug 261043, patch by Kyle Yuan

<kyle.yuan@sun.com>, r=peterv, sr=bryner, a=dbaron

widget/src/mac/nsMacEventHandler.cpp

@@ -1209,6 +1209,7 @@ ConvertKeyEventToContextMenuEvent(const nsKeyEvent* inKeyEvent, nsMouseEvent* ou
 {
   *(nsInputEvent*)outCMEvent = *(nsInputEvent*)inKeyEvent;
   
+  outCMEvent->eventStructType = NS_MOUSE_EVENT;
   outCMEvent->message = NS_CONTEXTMENU_KEY;
   outCMEvent->isShift = outCMEvent->isControl = outCMEvent->isAlt = outCMEvent->isMeta = PR_FALSE;