1958206 - Sticky positioned element inside subgrid is contained to top level grid, not to subgrid box.

Status: NEW

(Core :: Layout: Grid, defect)

Description

[Raul Bucata]

Environment:
Operating system: Mac OS X 10.15.7
Firefox version: Firefox 137.0

Steps to reproduce:

1. Navigate to: https://codepen.io/RJWadley/pen/pvoqwBr
2. Scroll the page and observe the output

Expected Behavior:
Sticky elements behave the same as in Chrome

Actual Behavior:
Sticky elements behave different compared to Chrome

Notes:

• Reproduces regardless of the status of ETP
• Reproduces in firefox-nightly, and firefox-release
• Does not reproduce in chrome

Created from https://github.com/webcompat/web-bugs/issues/152027

Comment 1

[Raul Bucata]

Attachment: chr vs ff.mp4

Comment 2

[Alice0775 White]

I can reproduce the issue on Nightly139.0a1 Windows11.

Regression window:
https://hg-edge.mozilla.org/integration/autoland/pushloghtml?fromchange=0ecb7e708492896313626fd3b3e3fbb8f32c42dc&tochange=eba2e80d463c05af9efe7aeba92fa82ff2d9f02a

Suspect: Bug 1679797

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Since nightly and release are affected, beta will likely be affected too.
For more information, please visit BugBot documentation.

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1679797

:emilio, since you are the author of the regressor, bug 1679797, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

I'm not sure I agree with the expectation. The sticky pos is laid out in the whole grid container, because its parent is a subgrid... Then again I guess the subgrid could be considered its own container too, for sticky pos purposes...

Ting-Yu, any strong opinions? Maybe we should fix bug 1679797 in some other way (like what I suggested in bug 1679797 comment 7 or so?).

Comment 6

[Emilio Cobos Álvarez (:emilio)]

Attachment: Test-case from comment 0

Comment 7

[[e-mail]]

Is it the same reason for broken smooth scrolling or should i open a different bug report?