User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/534.51.22 (KHTML, like Gecko) Version/5.1.1 Safari/534.51.22 Steps to reproduce: Apply CSS3 3D "-moz-perspective" and "overflow: hidden" to block level element Actual results: Child elements are rendered as if parent would not have a "perspective" attribute. Expected results: Perspective distortion should be applied to child elements. See Demo at http://www.eleqtriq.com/wp-content/static/demos/2011/mozbugs/

This seems likely to be related to the fact that overflow:hidden creates two frames, one nested inside the other (the inner one having an anonymous box style). I think the problem here is that nsDisplayTransform::GetResultingTransformMatrix (in layout/base/nsDisplayList.cpp) should replace: 2539 const nsStyleDisplay* parentDisp = nsnull; 2540 if (aFrame->GetParent()) { 2541 parentDisp = aFrame->GetParent()->GetStyleDisplay(); 2542 } with: const nsStyleDisplay *parentDisp = nsnull; nsStyleContext *parentStyleContext = aFrame->GetStyleContext()->GetParent(); if (parentStyleContext) { parentDisp = parentStyleContext->GetStyleDisplay(); } so that it gets the perspective from the style parent.

I think it would be good to get this fixed for Firefox 10 (where, if my memory is correct, 3-D transforms are a new feature).

Thanks for looking into this dbaron Requesting aurora/beta approval since this fixes a bug with our implementation of 3d transforms. Should be very low risk, and well covered by tests.

Comment on attachment 585545 [details] [diff] [review] Check style parent, instead of frame parent [Triage Comment] Please re-nominate once this has landed on m-c and gotten some bake time.

Comment on attachment 585545 [details] [diff] [review] Check style parent, instead of frame parent renominating per comment 4

https://hg.mozilla.org/releases/mozilla-beta/rev/0dfaeb9d662a https://hg.mozilla.org/releases/mozilla-aurora/rev/89407d03f983