/**
* Adds a validation rule.
* @param mixed rule type
* @param string message to display for invalid data
* @param mixed optional rule arguments
* @return FormControl provides a fluent interface
*/
public function addRule($operation, $message = NULL, $arg = NULL)
{
if ($operation === ':filled' and is_null($message)) {
$message = 'Choose %label';
}
return parent::addRule($operation, $message, $arg);
}
