Inove Wordpress theme menu overlap only in Firefox
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I'm working on a redesign of a company website. The site is in Wordpress and the live site was running an old version. Something like 2.3 or 2.5. I moved a copy of the complete site into a test directory that had the latest version of Wordpress (3.4). Immediately the submenus in the navigation began to overlap.

Screenshot here: http://img826.imageshack.us/img826/7219/overlaps.jpg

When I updated Wordpress on the live site the navigation did the same thing. So updating Wordpress definitely had something to do with it. Both the live and redesign sites are based on the Inove theme: http://inovedemo.wordpress.com/ The navigation on their demo site works fine in Firefox. 

So, can anyone help me out? I've been fighting with this on and off for weeks. I'd be happy to provide code if needed but there's a lot of it. The theme includes a menu.js file and there are several CSS IDs involved.

Long time browser, first time poster. Thank you in advance!