Kartikaya Gupta (email:kats@mozilla.staktrace.com) Reporter
	Description • 9 years ago

OS X desktop:
- Enable APZ
- Load the attached test page
- scroll with two-finger gesture on trackpad

Expected: blue thingy doesn't jitter
Actual: blue thingy jitters

APZ disabled doesn't have this problem.

	Kartikaya Gupta (email:kats@mozilla.staktrace.com) Reporter
	Comment 1 • 9 years ago

Note that even applying attachment 8624838 [details] [diff] [review] doesn't fix this.

	avada
	Comment 2 • 9 years ago

It looks like to me the same thing I mentioned in:
https://bugzilla.mozilla.org/show_bug.cgi?id=1133588#c12

Here's an url on the website where the background is persistently there: ipon.hu/hir/csokkenti_kaveri_apu_jainak_az_arat_az_amd/33519

But more importantly, I'm also getting the bug with the test case and I'm on windows 8.1 x64 and an Nvidia gts450.

	Botond Ballo [:botond] Assignee
	Comment 3 • 9 years ago

Also happens on Linux. I'm going to have a look at this.

	Botond Ballo [:botond] Assignee
	Comment 4 • 9 years ago

While investigating this with Matt, we discovered that when - as in this testcase - an element is both position:sticky and transformed, the transform is applied outside of the position:sticky.

We believe this is wrong; the position:sticky should be outside the transform. (Conceptually, the transformed content is position:sticky.)

This decision is made in nsIFrame::BuildDisplayListForStackingContext(), which wraps the display list into an nsDisplayStickyPosition first and then an nsDisplayTransform. Switching this order gives us the desired semantics, and fixes this bug.

	Botond Ballo [:botond] Assignee
	Comment 5 • 9 years ago

Bug 1176395 - When an element is both position:sticky and transformed, apply the position:sticky outside the transform. r=roc

Conceptually, the transformed content is position:sticky. position:fixed
behaves similarly.

	Botond Ballo [:botond] Assignee
	Comment 6 • 9 years ago

Bug 1176395 - Reftest. r=mstange

	Robert O'Callahan (:roc) (email my personal email if necessary)
	Comment 7 • 9 years ago

Comment on attachment 8697418 [details]
MozReview Request: Bug 1176395 - When an element is both position:sticky and transformed, apply the position:sticky outside the transform. r=roc

https://reviewboard.mozilla.org/r/27605/#review24873

	Robert O'Callahan (:roc) (email my personal email if necessary)
	Comment 8 • 9 years ago

Comment on attachment 8697419 [details]
MozReview Request: Bug 1176395 - Reftest. r=mstange

https://reviewboard.mozilla.org/r/27607/#review24875

	Botond Ballo [:botond] Assignee
	Comment 9 • 9 years ago

Try push good:

https://treeherder.mozilla.org/#/jobs?repo=try&revision=8790273a2bc3

Landed (with test as r=roc).

	Pulsebot
	Comment 10 • 9 years ago

https://hg.mozilla.org/integration/mozilla-inbound/rev/a64252105705
https://hg.mozilla.org/integration/mozilla-inbound/rev/2b827b7841f6

	Phil Ringnalda (:philor)
	Comment 11 • 9 years ago
bugherder

https://hg.mozilla.org/mozilla-central/rev/a64252105705
https://hg.mozilla.org/mozilla-central/rev/2b827b7841f6