add(form);
final TextField<String> firstname = new TextField<String>("firstname");
form.add(firstname);
firstname.setRequired(true);
final FormComponentFeedbackIndicator firstnameIndicator = new FormComponentFeedbackIndicator("firstIndicator");
firstnameIndicator.setIndicatorFor(firstname);
form.add(firstnameIndicator);
form.add(new TextField<String>("lastname"));
form.add(new DateTextField("birthday", "dd.MM.yyyy' um 'hh:mm"));
}