/**
* Adds a navigation button to the menu
*/
function addItem($topItem = self::BUTTONS_TOP)
{
$item = new Button();
$item->setSubStyle(Bgs1::BgEmpty);
if ($topItem == self::BUTTONS_TOP) {
$this->items[] = $item;
} else {
$this->bottomItems[] = $item;
}
$this->lastItem = $item;
}
