add: getCalendarManager().removeObserver(calCalendarManagerObserver); 
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);    pbi.removeObserver("calendar.", calPrefObserver);    var calendarList = document.getElementById("list-calendars-listbox");    calendarList.removeEventListener("select", onCalendarListSelect, true);}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/975fabc53135d3e5d5b000f5d4def29f8484d41f/calendarManagement.js/clean/calendar/resources/content/calendarManagement.js