add: var expandOrCollapseMenu = document.getElementById('menu_expandOrCollapse'); if(expandOrCollapseMenu) expandOrCollapseMenu.setAttribute("hidden", "true"); 
context: function HideMenus(){	var message_menuitem=document.getElementById('menu_showMessage');	if(message_menuitem)		message_menuitem.setAttribute("hidden", "true");}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/d5696d5addb95615f67ac72f6eb85cfe7ddaf3d6/messageWindow.js/buggy/mailnews/base/resources/content/messageWindow.js