submenuSelector not working

It seems that the submenuSelector is not working.

If if you define a submenu selector as following in the example.html it will stop working:

<!-- example.html: line 204 -->

$menu.menuAim({
   activate: activateSubmenu,
   deactivate: deactivateSubmenu,
   submenuSelector: ".popover"
});

Or do I use the option submenuSelector in a wrong way?