private void applyEndDateActivator() {
setEndDateActive(endDateActivator.isSelected());
}
private void selectDate(Receiver<Date> callback, Date current, String title) {
OverlayContainer overlayContainer = WidgetUtils.getOverlayContainerAncestor(getUi());
if (overlayContainer != null) {
DatePicker.selectFromOverlay(callback, overlayContainer, current, null, title);
} else {
Date start = DatePicker.selectFromDialog(current, UiUtils.getActiveWindow(), title);
callback.handle(start);