add: #ifdef MOZ_THUNDERBIRD case "cmd_install": return true; #endif 
context:   isCommandEnabled: function (aCommand)  {    var selectedItem = gExtensionsView.selected;    switch (aCommand) {    case "cmd_close":      return true;    case "cmd_useTheme":      return selectedItem && gCurrentTheme != selectedItem.getAttribute("internalName");    case "cmd_options":      return selectedItem && !selectedItem.disabled && selectedItem.getAttribute("optionsURL") != "";    case "cmd_about":      return !selectedItem || (selectedItem.disabled ? selectedItem.getAttribute("aboutURL") == "" : true);    case "cmd_homepage":      return (selectedItem && selectedItem.getAttribute("homepageURL") != "");    case "cmd_uninstall":      return selectedItem && selectedItem.getAttribute("locked") != "true";    case "cmd_update":      return true;    case "cmd_enable":      return selectedItem && selectedItem.disabled && !gExtensionManager.inSafeMode;    case "cmd_disable":      return selectedItem && selectedItem.getAttribute("locked") != "true" && !selectedItem.disabled;    case "cmd_movetop":      return (gExtensionsView.children[0] != selectedItem);    case "cmd_moveup":      return (gExtensionsView.children[0] != selectedItem);    case "cmd_movedn":      var children = gExtensionsView.children;      return (children[children.length-1] != selectedItem);    }    return false;  },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/8395/d9ba66a275a5e97dde21555f69d35ddeb63479d9/extensions.js/buggy/toolkit/mozapps/extensions/content/extensions.js