add:  getCompositeCalendar().removeObserver(agendaTreeView.calendarObserver); getCompositeCalendar().removeObserver(ltnCompositeCalendarObserver); getCalendarManager().removeObserver(ltnCalendarManagerObserver); 
context: function ltnFinish() {    var prefService = Components.classes["@mozilla.org/preferences-service;1"]                            .getService(Components.interfaces.nsIPrefService);    // Remove the pref observer    var pb2 = prefService.getBranch("");    pb2 = pb2.QueryInterface(Components.interfaces.nsIPrefBranch2);    pb2.removeObserver("calendar.", ltnPrefObserver);    return;}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/975fabc53135d3e5d5b000f5d4def29f8484d41f/messenger-overlay-sidebar.js/buggy/calendar/lightning/content/messenger-overlay-sidebar.js