function _removeAllAppointmentSelections(that, bRemoveOldSelection){
		if (bRemoveOldSelection) { //if !oEvent.ctrlKey
			_informPlanningCalendar.call(that, "DeselectAppointment");
		}
	}
Handles the situation when more than one appointment are selected and they must be deselected
when a single one is selected afterwards
@private