1844326 - Setting mousewheel.min_line_scroll_amount to a high value causes some site issues

Status: RESOLVED DUPLICATE of bug 1858984

(Core :: Layout: Scrolling and Overflow, defect, P3)

Description

[tgn-ff]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/117.0

Steps to reproduce:

1. Set mousewheel.min_line_scroll_amount to 70.
2. Open a youtube video.
3. Change its quality.

Actual results:

The video viewport height is reduced, leaving some pixels at the top out of view.

Expected results:

This is a regression from Bug 1842679.

The use case for that high value is that scrolling through bookmark folders is too fast in my opinion, which I workaround by changing mousewheel.default.delta_multiplier_y, which then makes scrolling slower even on webpages, so I compensate by increasing min_line_scroll_amount.

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=ae30a1ac484e1daea4fc77681a6edda7aba66aff&tochange=7ffbd7298f7b4d38aad4c5af4e08a00e626d2c09

Comment 1

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

:dlrobertson, since you are the author of the regressor, bug 1842679, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 2

[Dan Robertson (:dlrobertson)]

I have not been able to reproduce the issue when setting mousewheel.default.delta_multiplier_y or mousewheel.min_line_scroll_amount on macOS or Windows. I do not have a Linux box available at the moment. Could you upload a screen recording of the issue or were you able to confirm that the issue still occurs in troubleshoot mode?

Was the regression range discovered with mozregression?

Comment 3

[tgn-ff]

You only need to set mousewheel.min_line_scroll_amount to 70. Whether this depends on screen size, I don't know. If you have a high DPI monitor, you could try doubling/tripling the value. I have reproduced the bug on both Linux and Windows 11, in safe mode and a clean profile. I will attach the screen recording shortly.

Yes, I did use mozregression to find it.

Comment 4

[tgn-ff]

Attachment: ytbug.webm

Comment 5

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

The bug has a release status flag that shows some version of Firefox is affected, thus it will be considered confirmed.

Comment 6

[Dan Robertson (:dlrobertson)]

Marking as S3/P3 for now.

Comment 7

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

Set release status flags based on info from the regressing bug 1842679

Comment 8

[alvisebruniera]

Versions 118 and 119 are also affected.
The issue is also triggered when interacting with the video timeline.

Also when the video is in fullscreen, it also causes the page to scroll down a bit (and the viewport height is reduced as well).

Entering/exiting fullscreen mode reverts the issue untill the next interaction.

Comment 9

[tgn-ff]

Fixed by Bug 1858984.

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=462cb57adafa4ea04f0412a3089bd5926bdef63f&tochange=271462f27193e14ac7aa350072c5d150db55a4ba

Comment 10

[Botond Ballo [:botond]]

(In reply to tgn-ff from comment #9)

Fixed by Bug 1858984.

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=462cb57adafa4ea04f0412a3089bd5926bdef63f&tochange=271462f27193e14ac7aa350072c5d150db55a4ba

Thanks for checking! Marking as duplicate.