code: protected ValidationListener registerMessageReceiver(String propertyName, Messagable messageReceiver) {
  		MessagableValidationListener messagableValidationListener = new MessagableValidationListener(propertyName,
  				messageReceiver);
  		validationResults.addValidationListener(propertyName, messagableValidationListener);
  		messagableValidationListener.validationResultsChanged(validationResults);
  		return messagableValidationListener;
  	}
docs: Register a messageReceiver on a specific property. To keep things in
  sync, it also triggers a first time check. (validationResultsModel can
  already be populated)
  
  @param propertyName property to listen for.
  @param messageReceiver message capable component.
  @return {@link ValidationListener} created during the process.