/**
* Split menu tree into two distinct trees.
*
* @param mixed $length Name of child, child object, or numeric length.
* @return array Array with two trees, with "primary" and "secondary" key
*/
public function split($length)
{
$ret = parent::split($length);
$ret['secondary']->setTree($this->getTree()->copy($ret['secondary']), true);
return $ret;
}
