/**
  * @see wcf\system\option\user\group\IUserGroupOptionType::merge()
  */
 public function merge(array $values)
 {
     if (in_array(-1, $values)) {
         return -1;
     }
     return parent::merge($values);
 }
	/**
	 * @see	wcf\system\option\user\group\IUserGroupOptionType::merge()
	 */
	public function merge($defaultValue, $groupValue) {
		if ($defaultValue == -1) {
			return null;
		}
		else if ($groupValue == -1) {
			return $groupValue;
		}
		else {
			return parent::merge($defaultValue, $groupValue);
		}
	}
 /**
  * @see	\wcf\system\option\IOptionType::compare()
  */
 public function compare($value1, $value2)
 {
     if ($value1 == $value2) {
         return 0;
     }
     if ($value1 == -1) {
         return 1;
     } else {
         if ($value2 == -1) {
             return -1;
         }
     }
     return parent::compare($value1, $value2);
 }