add: menu.setAttribute('tooltiptext', category); 
context:             function menuFor(category) {                if(!menus[category]) {                    var menu = document.createElement('menu');                    menu.setAttribute('label', category);                    menuPopup.insertBefore(menu, menuPopup.getElementsByTagName('menuseparator')[0]);                    var popup = document.createElement('menupopup');                    menu.appendChild(popup);                    menus[category] = popup;                }                return menus[category];            }
meta: 1705	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/1705/e7d04a75eccffbfae19b816bcabf8e86a510a119/sameplace.js/buggy/chrome/content/sameplace.js