rem: Listbox.removeChild( SelectedItem ); 
add: if( SelectedItem ) Listbox.removeChild( SelectedItem ); 
context: function removeSelectedExceptionDate(){   var Listbox = document.getElementById( "exception-dates-listbox" );   var SelectedItem = Listbox.selectedItem;   Listbox.removeChild( SelectedItem );}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/4283a76f20455995a6c56f682bccd0b0705e1370/calendarEventDialog.js/clean/calendar/resources/content/calendarEventDialog.js