1176395 - position:sticky element jitters while scrolling with APZ

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect, P1)

Description

[Kartikaya Gupta (email:[e-mail])]

Attachment: Test case

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.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

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

Comment 2

[avada]

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.

Comment 3

[Botond Ballo [:botond] [away until July 9]]

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

Comment 4

[Botond Ballo [:botond] [away until July 9]]

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.

Comment 5

[Botond Ballo [:botond] [away until July 9]]

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

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.

Comment 6

[Botond Ballo [:botond] [away until July 9]]

Attachment: MozReview Request: Bug 1176395 - Reftest. r=mstange

Bug 1176395 - Reftest. r=mstange

Comment 7

[Robert O'Callahan (:roc) (email my personal email if necessary)]

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

Comment 8

[Robert O'Callahan (:roc) (email my personal email if necessary)]

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

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

Comment 9

[Botond Ballo [:botond] [away until July 9]]

Try push good:

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

Landed (with test as r=roc).

Comment 10

[Pulsebot]

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

Comment 11

[Phil Ringnalda (:philor)]

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