firefox shows modul 2 row but ie and chrome ok

www.e f g b i l i s i m .com.tr/index.php

if you open web site with ie or chrome its ok but if you open with firefox top menu- (user3) module seems 2 row.how can i fix this.

it looks same, maybe your FF is outdated

i dont use ff but customer said problem i installed latest stable one.
i closed one menu tab for a temporary solution.
but infact problem it is not fixed.
ff dont behave divs as chrome or ie...

I must see to be able to respond, you can set it on some temp page with all tabs so I could inspect.

it is now seeming 2 row in ff. for investigating.i opened closed menu tab.

Can not help without I see it first.