The two files have the same final DOM, so they should look identical. Based on layout/reftests/transform/abspos-1b.html

The problem is that in the dynamic one we make it a normal fixed-positioned child of the viewport rather than putting it on the absolute list of the element with transform, as we should do.

This is pretty trivial; just set things up in the dynamic case the same way we do when constructing from the top. I probably ought to add a test for both constructors somehow, but so far I only have Jesse's. Luckily I fixed the wrong constructor first, so I noticed there were two.

(In reply to comment #4) > I probably ought to add a test for both constructors somehow, but so far I only > have Jesse's. Luckily I fixed the wrong constructor first, so I noticed there > were two. I intended to help you out with this, but it looks to me as if we only call the four parameter constructor. I did some searching through MXR, and really this is the only instance of us constructing this object that I've found: http://mxr.mozilla.org/mozilla-central/source/layout/base/nsCSSFrameConstructor.cpp#7933 Is there something I'm missing? Also marking this as wanted 1.9.1 since we are touting our CSS-Tranform support in that release, this should get checked in to that branch too after it bakes.

Mostly we construct them on the stack, so you'll see "nsFrameConstructorState state(...)".

Fixed on mozilla-central: http://hg.mozilla.org/mozilla-central/rev/1fb56a23792d

Comment on attachment 350917 [details] [diff] [review] patch Somewhat nasty and pretty trivial-to-fix incremental layout bug related to a new feature (-moz-transform).

Shouldn't this be backported to 1.9.1, as this feature will be introduced in 3.1, and so the bug hasn't been shipped in a stable release yet?

dbaron already requested approval for the backport :)

Comment on attachment 350917 [details] [diff] [review] patch a191=beltzner

David, don't forget to land this!

Fixed on 1.9.1: http://hg.mozilla.org/releases/mozilla-1.9.1/rev/cd51ade5d696

verified FIXED on builds: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2a1pre) Gecko/20090721 Minefield/3.6a1pre ID:20090721044139 and Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.1pre) Gecko/20090720 Shiretoko/3.5.1pre ID:20090720042942