CMS Mozilla Firefox problem with section widget
 

Hi

When I use Mozilla Firefox 3.6.3 on my site and click on section widget not working but i test in Safari and IE 8 and works.Have any idea how fix it?Because many people using Mozilla Firefox and can't choose item in widget section menu

BTW:I try searching in forum about this problem but nothing find

Link to my site:

www.mobil-cestiny.cz

Thanks