rem: try 
add: try 
context: function getSidebarDatasourceURI(panels_file_id){    try     {        /* use the fileLocator to look in the profile directory          * to find 'panels.rdf', which is the         * database of the user's currently selected panels. */        var directory_service = Components.classes[DIR_SERV_CONTRACTID].getService(Components.interfaces.nsIProperties);        /* if <profile>/panels.rdf doesn't exist, get will copy         *bin/defaults/profile/panels.rdf to <profile>/panels.rdf */        var sidebar_file = directory_service.get(panels_file_id, Components.interfaces.nsIFile);        if (!sidebar_file.exists())        {            /* this should not happen, as GetFileLocation() should copy             * defaults/panels.rdf to the users profile directory */            debug("sidebar file does not exist");            return null;        }        var io_service = Components.classes[IO_SERV_CONTRACTID].getService(Components.interfaces.nsIIOService);        var file_handler = io_service.getProtocolHandler("file").QueryInterface(Components.interfaces.nsIFileProtocolHandler);        var sidebar_uri = file_handler.getURLSpecFromFile(sidebar_file);        debug("sidebar uri is " + sidebar_uri);        return sidebar_uri;    }    catch (ex)    {        /* this should not happen */        debug("caught " + ex + " getting sidebar datasource uri");        return null;    }}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/9421/6547e50d52d613914d789ed3b30011fb544330ad/nsSidebar.js/clean/suite/common/sidebar/nsSidebar.js