code: protected void parentStateChanged(PropertyChangeEvent evt) {
  		if (ENABLED_PROPERTY.equals(evt.getPropertyName())) {
  			enabledUpdated();
  		}
  		else if (READONLY_PROPERTY.equals(evt.getPropertyName())) {
  			readOnlyUpdated();
  		}
  	}
docs: Events from the parent form model that have side-effects on this form
  model should be handled here. This includes:
  
  <ul>
  <li><em>Enabled state:</em> when parent gets disabled, child should be
  disabled as well. If parent is enabled, child should go back to its
  original state.</li>
  <li><em>Read-only state:</em> when a parent is set read-only, child
  should be read-only as well. If parent is set editable, child should go
  back to its original state.</li>
  </ul>