password_field.addKeyListener( cancel_listener );
WindowKit.centerWindow( this );
validator = new FieldValidityChecker(
new EnableComponentAction( ok_button ),
new DisableComponentAction( ok_button ), false );
//noinspection unchecked
vcr = new ValueChangeRelay<JComponent>(
( ValueChangeRelay.ValueChangeListener<JComponent> )
validator.createVCRListener() );