Are you running Catalyst 12.9 beta? If so uninstall it and install 12.8 release. Fixed it for me.
No, i was using version 12.6 and now i'm updating to v12.8. Anyway those glitches disappeared with yesterday's nightly but new ones appeared (bad rendering of text in chrome)
Thanks for the response.
Just now, I saw that Thunderbird already has Australis so I decided to check it out. It looks awful on Windows 8 right now so I'm willing to wait
The Windows 7 UI I tried before looks awesome though.
Quick reminder, Australis is more than just the tabs, which is what I assume you are referring to. They're making Australis-type changes every few releases.