--- a/layout/xul/nsMenuBarListener.cpp
+++ b/layout/xul/nsMenuBarListener.cpp
@@ -322,16 +322,27 @@ nsMenuBarListener::KeyPress(nsIDOMEvent*
         aKeyEvent->StopPropagation();
         aKeyEvent->PreventDefault();
       }
     }
 #ifndef XP_MACOSX
     // Also need to handle F10 specially on Non-Mac platform.
     else if (nativeKeyEvent->mMessage == eKeyPress && keyCode == NS_VK_F10) {
       if ((GetModifiersForAccessKey(keyEvent) & ~MODIFIER_CONTROL) == 0) {
+        // If the keyboard event should activate the menubar and will be
+        // sent to a remote process, it should be executed with reply
+        // event from the focused remote process.  Note that if the menubar
+        // is active, the event is already marked as "stop cross
+        // process dispatching".  So, in that case, this won't wait
+        // reply from the remote content.
+        if (nativeKeyEvent->WillBeSentToRemoteProcess()) {
+          nativeKeyEvent->StopImmediatePropagation();
+          nativeKeyEvent->MarkAsWaitingReplyFromRemoteProcess();
+          return NS_OK;
+        }
         // The F10 key just went down by itself or with ctrl pressed.
         // In Windows, both of these activate the menu bar.
         mMenuBarFrame->SetActiveByKeyboard();
         ToggleMenuActiveState();
 
         if (mMenuBarFrame->IsActive()) {
 #ifdef MOZ_WIDGET_GTK
           // In GTK, this also opens the first menu.