private function parsePanelRow($fields, PanelRowInterface $panelRow)
    {
        // Parse each type.
        foreach ($fields as $field) {
            switch ($field) {
                case 'sort':
                    $this->parsePanelSort($panelRow);
                    break;

                case 'limit':
                    $this->parsePanelLimit($panelRow);
                    break;

                case 'filter':
                    $this->parsePanelFilter($panelRow);
                    break;

                case 'search':
                    $this->parsePanelSearch($panelRow);
                    break;

                case 'submit':
                    $this->parsePanelSubmit($panelRow);
                    break;

                default:
                    break;
            }
        }
    }