protected function _isSortEnabled()
    {
        if (!isset($this->controller->sortFields)) {
            return false;
        }

        foreach ($this->controller->sortFields as $field) {
            if (isset($field['actions']) &&
                is_array($field['actions']) &&
                in_array($this->action, $field['actions'])
            ) {
                return true;
            }
        }

        return false;
    }