public function displayHeaderCell()
    {
        if (!$this->visible) {
            return;
        }

        $th_tag = new SwatHtmlTag('th', $this->getThAttributes());
        $th_tag->scope = 'col';

        $colspan = $this->getXhtmlColspan();
        if ($colspan > 1) {
            $th_tag->colspan = $colspan;
        }

        $th_tag->open();
        $this->displayHeader();
        $th_tag->close();
    }