From Bugzilla Helper: User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:0.9+) Gecko/20010522 BuildID: 2001052204 Take a look at the four tabs from the screenshot...
This occurs in new modern theme for Linux and Mac as well.
*** Bug 83746 has been marked as a duplicate of this bug. ***
themes triage: moving to 0.9.3. UGLY.
Verified on windows 98 (commercial build: 2001-06-18-09-trunk).