bug 126439 - Alt+F4 beeps in some window

only beep if the menu bar is active, instead of whenever a matching shortcut key isn't found
r=pink, sr=blake, a=asa

layout/xul/base/src/nsMenuBarFrame.cpp

@@ -286,9 +286,11 @@ nsMenuBarFrame::FindMenuWithShortcut(PRUint32 aLetter)
   // didn't find a matching menu item
 #ifdef XP_WIN
   // behavior on Windows - this item is on the menu bar, beep and deactivate the menu bar
-  nsCOMPtr<nsISound> soundInterface = do_CreateInstance("@mozilla.org/sound;1");
-  if (soundInterface)
-    soundInterface->Beep();    
+  if (mIsActive) {
+    nsCOMPtr<nsISound> soundInterface = do_CreateInstance("@mozilla.org/sound;1");
+    if (soundInterface)
+      soundInterface->Beep();
+  }
 
   DismissChain();
 #endif  // #ifdef XP_WIN