1850559 - After every Firefox update, dropdown lists and some pages start to have overlay scrollbars instead of normal ones

Status: REOPENED

(Core :: Widget, defect, P5)

Description

[5silentrain]

Attachment: "Automatically based on mouse or trackpad" option.png

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/117.0

Steps to reproduce:

1. Connect a regular mouse with a scroll wheel to your Mac.
2. In the System Settings, in the "Appearance" section, enable the "Automatically based on mouse or trackpad" option. Screenshot: https://i.imgur.com/GP9qWf5.png
3. Update Firefox to the new version.

Actual results:

Dropdown lists and some pages (such as about:support and about:config) start showing overlay scrollbars instead of normal ones. To fix this, after updating Firefox, you have to unload it from memory by pressing the Command + Q key combination and run it again.

Screenshots:
Dropdown list: https://i.imgur.com/JExfbaz.png
Dropdown list: https://i.imgur.com/L8bORhr.png
about:support page: https://i.imgur.com/oMvZUhm.png

Comment 1

[5silentrain]

Attachment: Dropdown list 1.png

Comment 2

[5silentrain]

Attachment: Dropdown list 2.png

Comment 3

[5silentrain]

Attachment: about-support page.png

Comment 4

[Ada C.]

Hi, 5silentrain

I tried to reproduce this on latest Nightly using macOS 11.6 ARM, but I didn't manage to recreate it. Could you tell me the macOS version you're using?

Comment 5

[5silentrain]

I've seen this behavior over the years using Firefox on macOS. Try upgrading not to a minor release, but to a major one (for example, from version 116 to version 117). After Firefox is automatically updated, it restarts. I observe this bug exclusively at this moment, right after the browser restarted after the update. If you unload Firefox from memory by pressing the Cmd + Q key combination, and then start it again, the scrollbars become normal.

Comment 6

[5silentrain]

Okay, I updated from dev version 118 to version 119. The scrollbars have not changed 👌

Comment 7

[5silentrain]

Today I updated from the stable version 117.0.1 to 118.0 and I still see overlay scrollbars instead of the usual ones. Apparently this bug has been fixed since version 118 🤔

Comment 8

[5silentrain]

You can close this bug report.

Comment 9

[5silentrain]

Apparently this bug has been fixed since version 118 🤔

More precisely, from version 119 🙂

Comment 10

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

The Bugbug bot thinks this bug should belong to the 'Firefox::Settings UI' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 11

[Molly Howell (she/her) (mostly inactive)]

Closing as per comment 8.

Comment 12

[5silentrain]

Very strange. Today I updated from the stable version 118.0.2 to 119.0, and the scrollbars did not change. But when the dev version was updated from 119.0 Beta 9 to 120.0 Beta 1, the scrollbars became overlays again.
I think this bug is still present in Firefox. Please open my bug report.

Comment 13

[5silentrain]

Screenshot: https://i.imgur.com/3bKNP6U.png

Comment 14

[5silentrain]

Attachment: Firefox Developer Edition from 119.0 Beta 9 to 120.0 Beta 1

Comment 15

[5silentrain]

Today I updated from Firefox Developer Edition 120.0 Beta 1 to 120.0 Beta 2. After this minor update, overlay scrollbars appeared again.