protected function displayGroupHeader($row)
    {
        $div_tag = new SwatHtmlTag('div');
        $div_tag->class = 'swat-tile-view-group';

        if ($this->header_current === null) {
            $div_tag->class .= ' swat-tile-view-first-group';
        }

        $div_tag->open();

        $heading_tag = new SwatHtmlTag('h4');
        $heading_tag->open();
        $this->displayRenderersInternal($row);
        $heading_tag->close();

        $div_tag->close();
    }