1913513 - Horizontal scrollbar briefly appears when wallpapers sub-sections animate on/off-screen

Status: NEW

(Firefox :: New Tab Page, defect)

Description

[Daniel Holbert [:dholbert]]

STR:

1. Click cog on new-tab page
2. Click any of the options for Wallpapers (Solid Colors, Abstract, or Photographs), and watch the bottom right of your Firefox window.

ACTUAL RESULTS:
A horizontal scrollbar briefly appears while the wallpaper section is animating on/off-screen; and then the scrollbar disappears when the animation ends.

EXPECTED RESULTS:
No such temporary scrollbar.

See also bug 1913452 about another unnecessary scrollbar here; unlike that bug, this one here only happens during the animation, and the patch on that other bug doesn't help with this bug here.

I'm using Firefox 131.0a1 (2024-08-16) on Linux (Ubuntu 22.04).

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: screencast showing the bug (watch the bottom right corner)

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: screencast showing the bug after enabling "always show scrollbars" (which makes it a bit more obvious)

The sleekness of the overlay scrollbar (our default configuration on Linux) makes this kind of subtle, but if you have "always show scrollbars" on, then the unnecessary scrollbar is much more obvious; here's a screencast with that config.

Comment 3

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

The severity field is not set for this bug.
:amy, could you have a look please?

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