You need change file:
modules/blocktopmenu/blocktopmenu.php
foreach ($pages as $page)
{
$cms = new CMS($page['id_cms'], (int)$id_lang);
$links = $cms->getLinks((int)$id_lang, array((int)$cms->id));
$selected = ($this->page_name == 'cms' && ((int)Tools::getValue('id_cms') == $page['id_cms'])) ? ' class="sfHoverForce"' : '';
if (strpos($cms->meta_description, 'REDIRECT:') !== False) {
$this->_menu .= '<li '.$selected.'>';
$this->_menu .= '<a href="'.str_replace("REDIRECT:", "", $cms->meta_description).'">'.$cms->meta_title.'</a>';
$this->_menu .= '</li>';
}
else {
$this->_menu .= '<li '.$selected.'>';
$this->_menu .= '<a href="'.$links[0]['link'].'">'.$cms->meta_title.'</a>';
$this->_menu .= '</li>';
}
}
Don't forget, if you need deactivate top category item link of CMS menu to list of CMS articles, you need change too this section (only remove code inside href):
case 'CMS_CAT':
$category = new CMSCategory((int)$id, (int)$id_lang);
if (count($category))
{
$this->_menu .= '<li><a href="" title="'.$category->name.'">'.$category->name.'</a>';
$this->getCMSMenuItems($category->id);
$this->_menu .= '</li>'.PHP_EOL;
}
break;