Navigation Bar not working on Samsung S2

[leadelazer]

I set up a website with dw minion for our kindergarten and so far everything went fine. Unfortunately some people are not able to use the site with their smartphones (especially with the default android browser) because the navigation bar is completely broken, not showing any menu items when the sidebar is open but then sidebar contents will overlay the rest of the layout when navbar got closed again. Unfortunately I can't emulate these devices to find out what could cause the problem. So it would be great if you could check it out! Thanks