add:  var calendarList = document.getElementById("list-calendars-listbox"); calendarList.removeEventListener("select", onCalendarListSelect, true);  
context: function finishCalendarManager() {    // Remove the category color pref observer    var pbi = prefService.getBranch("");    pbi = pbi.QueryInterface(Components.interfaces.nsIPrefBranch2);    pbi.removeObserver("calendar.category.color.", categoryPrefObserver);}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/a0eaf619262700a166ba6ba05cb60df4b30ed70f/calendarManagement.js/buggy/calendar/resources/content/calendarManagement.js