bug 223534: alt+enter for opening URL in new tab doesn't work at all. Fix the problem by preventing Alt+Enter default action in the bubbling phase instead of the capturing one so that Alt+Enter can be handled and still doesn't beep on WinXP.

browser/base/content/browser.js

@@ -397,7 +397,7 @@ function delayedStartup()
   
   gBrowser.addEventListener("load", function(evt) { setTimeout(loadEventHandlers, 0, evt); }, true);
 
-  window.addEventListener("keypress", ctrlNumberTabSelection, true);
+  window.addEventListener("keypress", ctrlNumberTabSelection, false);
 
   if (gMustLoadSidebar) {
     var sidebar = document.getElementById("sidebar");