public function __construct($sName, $sValue = '', array $aProperties = null)
 {
     if (!is_array($aProperties)) {
         $aProperties = array();
     }
     if (!empty($sValue)) {
         $aProperties['value'] = $sValue;
     }
     // We remove the session of the hidden fields
     unset($_SESSION['pfbc'][\PFBC\Form::getFormId()]['values'][$sName]);
     parent::__construct('', $sName, $aProperties);
 }