1994643 - Tab group hover preview does not show reliably

Status: RESOLVED FIXED

(Firefox :: Tabbed Browser, defect)

Description

[Merci chao]

Attachment: record.mp4

Steps to reproduce:

The preview panel sometimes does not open when the cursor moves quickly:

1. Hover a tab;
2. Hover a collapsed group fast before the tab preview shows.

Actual results:

The group hover preview often can't show up.

Expected results:

The preview panel should show reliably.

Comment 1

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Hello, thank you for the bug report!
Managed to reproduce this issue on:

• Firefox Nightly 146.0a1;
• Firefox 145.0b7;

Tested and reproduced on:

• Windows 10;
• macOS 15;
• Ubuntu 22;

Setting as NEW so the developing team can have a look.

Comment 2

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

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

For more information, please visit BugBot documentation.

Comment 3

[Stephen Thompson [:sthompson]]

Hey Jeremy, do you think this was fixed with your recent patches?

Comment 4

[Jeremy Swinarton]

Hi :sthompson, yes, this should have been fixed by https://phabricator.services.mozilla.com/D270239, which landed late afternoon on October 28.

:oardelean, could you take a look again and confirm that it's no longer possible to reproduce? Thank you!

Comment 5

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Hello,

I can confirm the fix on the latest Firefox Nightly build(2025-11-06), as the tab group preview is now reliably shown every time on hover.

Tested on Windows 10, Ubuntu 22, macOS 15.