public boolean updateEventAlreadyInSync(final Kalendar cal, final KalendarEvent kalendarEvent) {
OLATResourceable calOres = getOresHelperFor(cal);
CoordinatorManager.getCoordinator().getSyncer().assertAlreadyDoInSyncFor(calOres);
Kalendar loadedCal = getCalendarFromCache(cal.getType(),cal.getCalendarID());
loadedCal.removeEvent(kalendarEvent); // remove old event
loadedCal.addEvent(kalendarEvent); // add changed event
boolean successfullyPersist = persistCalendar(loadedCal);
// inform all controller about calendar change for reload
CoordinatorManager.getCoordinator().getEventBus().fireEventToListenersOf(new KalendarModifiedEvent(cal), OresHelper.lookupType(CalendarManager.class));
return successfullyPersist;
}