Comment 18 for bug 183333

(In reply to comment #9)
> Nautilus doesn't put a dividing line between the tabs and the content, but
> draws a border around the entire content area, i.e. on all sides, which we
> certainly don't want in Firefox.

Sure, and I'm not suggesting we do that. I was just pointing out that the "our look matches the native Gnome apps" argument (from comment 4) doesn't seem to have a lot of support. (at least, not anymore, with newish versions of Gnome apps -- it might have been more valid a few years back.)