public function getPreviewActionAttribute()
    {
        if ($this->changedModel
            && $this->changedModel->uri
            && $this->action != 'deleted') {
            return sprintf('<a href="%s" target="_blank"
                class="glyphicon glyphicon-bookmark js-tooltip"
                title="%s" data-placement="left"></a>',
                $this->preview_url,
                __('decoy::changes.standard_list.preview'));
        } else {
            return '<span class="glyphicon glyphicon-bookmark disabled"></span>';
        }
    }