1529324 - background-attachment fixed moves when inside position:fixed element

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect, P3)

Description

[maixner.david]

Attachment: fixed-attachment-problem.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.109 Safari/537.36

Steps to reproduce:

1. go to https://liveweave.com/7inLDR
2. close developer tools - cannot be reproduced with dev tools open
3. in preview window scroll down.
4. click in page
5. scroll up

Actual results:

When scrolling down, you can fixed attachment is scrolling
When scrolling up, you can see page behind "popup".

Expected results:

Background image shouldnt move when scrolling.
You shouldnt see page behind background-image.

Everything seems to be fine, when i have dev tools opened, or some moving element is present on page.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

That page only shows "Hello Weaver!" here, which doesn't look like the screenshot?

Comment 2

[maixner.david]

I am sorry, it seems i cannot make it public.

Codepen link : https://s.codepen.io/masner/debug/jdRBza/VJrxxVjWVLBr

Note: if you use regular codepen view (editor), everything seems to be fine.

Comment 3

[maixner.david]

Also adding regular codepen link, so you can see source : https://codepen.io/masner/pen/jdRBza

Comment 4

[Alice0775 White]

DIsableing APZ fixes the problem.

There are two regression.
#1 The fixed image can be scrolled
#2 Background blue element becomes visible when click the scrolled image

#1
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=eca3a6b94f7934377b099ddb22ae9c91f340cbfc&tochange=9066ef31441959ae15b83d59395ed34d3ed03c0a

suspect: Bug 1192910

#2
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=38d9a0fa515abfc32aced8d09704d40c47c6ef23&tochange=5746c9b9db68fc00cce51b6cd873f403e0caaee6

suspect: Bug 1298218

Comment 5

[Alice0775 White]

(In reply to Emilio Cobos Álvarez (:emilio) from comment #1)

That page only shows "Hello Weaver!" here, which doesn't look like the
screenshot?

In this case, you should reload the page to see the testcase.

Comment 6

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

(In reply to maixner.david from comment #2)

Codepen link : https://s.codepen.io/masner/debug/jdRBza/VJrxxVjWVLBr

This has expired

(In reply to maixner.david from comment #3)

Also adding regular codepen link, so you can see source : https://codepen.io/masner/pen/jdRBza

This behaves normally

(In reply to maixner.david from comment #0)

1. go to https://liveweave.com/7inLDR
2. close developer tools - cannot be reproduced with dev tools open
3. in preview window scroll down.
4. click in page
5. scroll up

I can see the problem here, but it goes away with WR enabled. Most likely a bug in AsyncCompositionManager/APZ code where we're not async-transforming the element properly.

Comment 7

[Botond Ballo [:botond]]

Attachment: Testcase

Here is the testcase in plain form, bereft of expiry dates and other fluff.

Comment 8

[Botond Ballo [:botond]]

On this page, the fixed background is inside a scroll frame which is inside a position:fixed element. Not terribly surprising that we get this wrong.

Comment 9

[Patricia Lawless]

Bulk change of P3 carryover bugs to wontfix for 68.

Comment 10

[Liz Henry (:lizzard) (relman/hg->git project)]

Happy to take a patch for 70 but since this is triaged and set to P3 priority I'm setting it as fix-optional.
That will remove the bug from weekly regression triage.