1984732 - Tab opening and closing animations should be skipped when switching tabs in tab group hover preview

Status: VERIFIED FIXED

(Firefox :: Tabbed Browser, defect, P2)

Description

[Amy Lee [:amylee] UX]

Attachment: Screen Recording 2025-08-22 at 2.56.17 PM.mov

Steps to reproduce [can add screenshots or video recordings for reference]:

1. Create a tab group with a few tabs in it
2. Collapse the group (with an active tab inside it)
3. Hover over the tab group label to trigger the tab group hover preview
4. Switch between tabs in the hover preview

Expected behavior [What should have happened?]:
The tab should just switch to the selected tab (no animation)

Actual behavior [What actually happened?]:
A swiping animation happens when you're switching between tabs

Comment 1

[Stephen Thompson [:sthompson]]

Putting this under bug 1971232. The animation is from our standard tab styles that animate the tab size when they appear/disappear.

Comment 2

[Dão Gottwald [:dao]]

This seems like a cosmetic issue, i.e. an S4?

Comment 3

[Jeremy Swinarton]

Attachment: Bug 1984732: Suppress animation when switching between tabs in a collapsed tab group r?dwalker,sthompson

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/3e1a58787c7e
https://hg.mozilla.org/integration/autoland/rev/a7e44acdaa21
Suppress animation when switching between tabs in a collapsed tab group r=dwalker,sthompson,desktop-theme-reviewers,tabbrowser-reviewers,dao

Comment 5

[pstanciu]

https://hg.mozilla.org/mozilla-central/rev/a7e44acdaa21

Comment 6

[Simona Badau, Desktop QA]

Reproduced the initial issue using Firefox 145 on Windows 11 x64.

Verified as fixed using Firefox 146.b2 on Windows 11 x64, Ubuntu 24.04 and macOS 15 - no swiping animation occurs when switching between tabs in a tab-group hover preview.