final TextBox tb = TextBoxFactory.getTextBox( DataType.TYPE_STRING );
tb.setValue( at.getValue() );
tb.setEnabled( false );
} else {
final PopupDatePicker dp = new PopupDatePicker( false );
dp.addValueChangeHandler( new ValueChangeHandler<Date>() {
public void onValueChange( ValueChangeEvent<Date> event ) {
at.setValue( PopupDatePicker.convertToString( event ) );
}