Starting with today's Linux nightly, the tab bar's scroll buttons are too narrow. The arrow seems to overflow the button. I suspect this is a regression from bug 585069.
*** Bug 678991 has been marked as a duplicate of this bug. ***
(In reply to Dão Gottwald [:dao] from comment #0)
> I suspect this is a regression from bug 585069.
The first bad revision is:
user: Neil Deakin <firstname.lastname@example.org>
date: Fri Aug 05 15:24:24 2011 -0400
summary: Bug 585069, support ratio scaling for xul images, r=dbaron
Should be fixed by 677091.