Linked testpage should be fairly self-explanatory. A scrollbar appears in Firefox 12, but not in anything else. This is a reduction of an existing product page.

CCing at Ms2ger's request

Looks like the behavior changed sometime in the last week here. Nemo, can you find the regression range?

Actually, nevermind. Range is http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=58e933465c36&tochange=5c2bc94d359c Chances are, a regression from bug 524925.

Changed title since table-layout: fixed appears to be irrelevant to causing the bug. Good to know you guys are on it.

I'll take a look...

table row-group row cell Fx9: clip v v clip Chrome18: clip clip s clip Opera12: clip v+s v+s clip IE10: clip v+s v+s clip Nightly: clip v+s v+s clip (v = visual overflow, s = scrollable overflow)

The old behavior doesn't make sense to me, I think it was unintentional (a bug). The new behavior is compatible with Opera and IE.

Hm. You're right. I thought I'd tested whether this worked in IE8, but it doesn't. Just Firefox and Chrome stable. Ok. Fair enough.

Sure enough, adding overflow: hidden; to the table instead of the tbody works fine. TBH I don't see the distinction. Seems that if clipping to the table works, clipping to the tbody should work too, but since it so happens that table works in IE8 as well (apart from some other WTF behaviour that luckily doesn't impact the actual page) I'm totally fine w/ that workaround. Thanks for your help!

Resolving as invalid since I think the change from visual to visual+scrollable overflow is an improvement and compatible with what other UAs do. Note that 'overflow' on row-groups might change in the future (bug 674214).