protected function validateCreatorOrder()
    {
        $field = 'creator';
        $value = $this->getSubmitted($field);

        if (!isset($value) && $this->isUpdating()) {
            $this->unsetSubmitted($field);
            return null;
        }

        if (empty($value)) {
            return null;
        }

        $label = $this->translation->text('Creator');

        if (!is_numeric($value)) {
            $this->setErrorNumeric($field, $label);
            return false;
        }

        $user = $this->user->get($value);

        if (empty($user)) {
            $this->setErrorUnavailable($field, $label);
            return false;
        }

        return true;
    }