add: var folderURI = GetSelectedFolderURI(); var server = GetServer(folderURI); if (!(server.canCompactFoldersOnServer)) return false;  
context: function IsCompactFolderEnabled(){    var folderOutliner = GetFolderOutliner();    var startIndex = {};    var endIndex = {};    folderOutliner.outlinerBoxObject.selection.getRangeAt(0, startIndex, endIndex);    if (startIndex.value < 0)         return false;    var folderResource = GetFolderResource(folderOutliner, startIndex.value);    if (! folderResource)         return false;    return GetFolderAttribute(folderOutliner, folderResource, "CanCompact") == "true" && isCommandEnabled("cmd_compactFolder");}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/65d20cc280a152b552ffab6306bea0b601bfef7f/mailWindowOverlay.js/buggy/mailnews/base/resources/content/mailWindowOverlay.js