2003516 - 444.hu - Choppy scrolling with the menu open

Status: REOPENED

(Core :: CSS Parsing and Computation, defect, P3)

Description

[Calin Tanase (PTO until 15th of May)]

Attachment: image.png

Environment:
Operating system: Windows 10
Firefox version: 145/147

Steps to reproduce:

1. Go to https://444.hu/2025/11/12/van-mar-olyan-szijjarto-szereples-amit-tobb-orosz-lathatott-mint-magyar
2. Click on "Menü" button.

Expected Behavior:
The menu gets shown.

Actual Behavior:
Nothing happens.

Notes:

1. Reproducible regardless of the ETP status
2. Not reproducible on Firefox Release and Chrome
3. Issue found during the Anchor-positioning QA testing phase

Comment 1

[David Shin[:dshin]]

Interesting, with mozregression --launch 2025-12-01 -a https://444.hu/2025/11/12/van-mar-olyan-szijjarto-szereples-amit-tobb-orosz-lathatott-mint-magyar I see the menu, but quite offset from the correct position.

Comment 2

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

Since the status is marked as affected for nightly and as unaffected for release, is it affected or unaffected for beta?
For more information, please visit BugBot documentation.

Comment 3

[David Shin[:dshin]]

Similar issue with Bug 2003537, we anchor to the share button instead of the menu button. Root cause is anchor-scope and display: contents interacting poorly, likely.

I also think the menu doesn't scroll well, which is likely bug 2002789

Comment 4

[Emilio Cobos Álvarez [:emilio]]

Also fixed by bug 1987086

Comment 5

[Emilio Cobos Álvarez [:emilio]]

Yeah so the menu works after bug 1987086. David, how critical do you think the choppy scrolling is? Do you think we can live with it for the initial release? (I think so, but we should prioritize that bug since it affects live sites)

Comment 6

[David Shin[:dshin]]

Yeah, it has to do with anchor being under <header> which is sticky.
... Which is proving a bit annoying because sticky's normal position contains some offset contributed by scroll, and some contributed by inset.

It's not critical because I think people will generally not scroll while a menu is out like that, but still looks pretty bad & confusing.
Will be the next item for me after bug 1924792 (Which seems to affect more sites & makes the menu hard-to-reach/read).

Comment 7

[Emilio Cobos Álvarez [:emilio]]

This works now, probably due to some of Tim's async scrolling fixes. Tim do you know which off-hand? If so care duping?

Comment 8

[Timothy Nikkel (:tnikkel)]

I tested this, for me the choppy scrolling hasn't changed since the menu started showing up correctly, including in the latest nightly.

The behaviour seems about the same whether I have apz.async_scroll_css_anchor_pos set to true or false. So doesn't seem related to async scrolling. Probably related to one of the other bugs mentioned here.

Comment 9

[Emilio Cobos Álvarez [:emilio]]

Hmm, it seemed to scroll smoothly for me yesterday when I tested it but maybe I didn't test long enough?

Comment 10

[Timothy Nikkel (:tnikkel)]

It seems to show up immediately for me. Maybe a platform difference? I'm testing on macos.