add: var customizePopup = document.getElementById("CustomizeMailToolbar"); customizePopup.removeAttribute("disabled"); 
context: function MailToolboxCustomizeDone(aToolboxChanged){  // Update global UI elements that may have been added or removed  // Re-enable parts of the UI we disabled during the dialog  var menubar = document.getElementById("mail-menubar");  for (var i = 0; i < menubar.childNodes.length; ++i)    menubar.childNodes[i].setAttribute("disabled", false);  //var cmd = document.getElementById("cmd_CustomizeToolbars");  //cmd.removeAttribute("disabled");  // make sure our toolbar buttons have the correct enabled state restored to them...  if (this.UpdateMailToolbar != undefined)    UpdateMailToolbar(focus); }
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/a350b67cd7b774ed2786b987b5af01da65fb1a31/mailCore.js/buggy/mail/base/content/mailCore.js