code: protected void childStateChanged(PropertyChangeEvent evt) {
  		super.childStateChanged(evt);
  		if (ValidationResultsModel.HAS_ERRORS_PROPERTY.equals(evt.getPropertyName())) {
  			hasErrorsUpdated();
  		}
  	}
docs: {@inheritDoc}
  
  Additionally the {@link DefaultFormModel} adds the event:
  
  <ul>
  <li><em>Has errors event:</em> if the validation results model
  contains errors, the form model error state should be revised as well as
  the committable state.</li>
  </ul>
  
  Note that we see the {@link ValidationResultsModel} as a child model of
  the {@link DefaultFormModel} as the result model is bundled together with
  the value models.