rem: clone.append( (KCal::Event*)dummy->clone()  );
add: clone.append( (KCal::Todo*)dummy->clone() );
context:     void cloneList(const QPtrList<KCal::Event>& old, QPtrList<KCal::Event> &clone  ) {        KCal::Event* dummy;        QPtrListIterator<KCal::Event> it(old );        for ( ; it.current(); ++it ) {            dummy = it.current();            clone.append( (KCal::Event*)dummy->clone()  );        }    }