rem: setCalendarManagerUI(); 
add: var item = getListItem(aCalendar); if (item) { document.getElementById("list-calendars-listbox").removeChild(item); } 
context:     onCalendarUnregistering: function(aCalendar) {        setCalendarManagerUI();    },
meta: 5459	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5459/676ab5473071609124ee2ae9a2840b85f281cc02/calendarManagement.js/buggy/calendar/resources/content/calendarManagement.js