public function getPortableType()
    {
        $type = false;
        switch ($this->getFieldXType()) {
            case 'modx-combo-template':
                $type = 'template';
                break;

            case 'modx-combo-source':
                $type = 'media-source';
                break;

            default:
                if (isset($this->portable_settings[$this->getFieldKey()])) {
                    $type = $this->portable_settings[$this->getFieldKey()];
                }
        }
        return $type;
    }