Firefox top bar crashing

What version of Ubuntu and what environment you use ?

Please give additional info , open a terminal and give the results of these commands

~$ lsb_release -rcd ; uname -r
~$ echo $DESKTOP_SESSION
~$ dpkg -l | grep -i firefox

Thanks

Those things go into the global menu at the top of the screen. Hover your mouse over the topmost bar and it will all be there.

Hi NikTh,

Asl follows:

#1
Description: Ubuntu 12.04.1 LTS
Release: 12.04
Codename: precise
3.2.0-32-generic-pae
(it's actually Zorin 6 final 32bit but it's build on Ubuntu 12)

#2
zorin_desktop

#3
ii firefox 16.0.2+build1-0ubuntu0.12.04.1 Safe and easy web browser from Mozilla
ii firefox-globalmenu 16.0.2+build1-0ubuntu0.12.04.1 Unity appmenu integration for Firefox
ii xul-ext-ubufox 2.1.1-0ubuntu0.12.04.1 Ubuntu-specific configuration defaults and apt support for Firefox

#4
Hoovering doesn't help.
When I move around firefox window I can see breaking line between top bar and rest of program. Than after time it disappears. Still didn't figured out what's causing it.

http://www.zoringroup.com/forum/viewforum.php?f=3

Zorin isn't supported in any of the Ubuntu support channels. I suggest you post on the link above.

Is Firefox supported in Ubuntu than ? Who supports it/who is the resolver ?

Yes Ubuntu supports Firefox. You are not using Ubuntu, you are using ZorinOS, which isn't supported here.

I am using zorin as mentioned which is solely build on ubuntu 12.04 LTS. The only differences are visual, therefore I do not agree that zorin isn't a ubuntu. Furthermore, it seems to be a problem with Compiz which is obviously one of the core components of ubuntu.

Its a totally different community. Ubuntu is based on Debian but if you ask for Ubuntu support in Debian support channels you will be pointed elsewhere. NONE of the "Ubuntu based" distros are supported in the Ubuntu channels. These include (but are not limited to):
-Mint
-BackTrack
-Mint
-Zorin
-PearOS
-ElementaryOS

and so on, the support is separate.