2006572 - The right tab name and icon slightly move when the Split View is selected

Status: RESOLVED FIXED

(Firefox :: Tabbed Browser: Split View, defect, P3)

Description

[Alexandru Trif, Desktop Test Engineering [:atrif]]

Found in

• 148.0a1 (2025-12-16)

Affected versions

• 148.0a1 (2025-12-16)

Tested platforms

• Affected platforms: Ubuntu 24, Windows 11, macOS 26
• Unaffected platforms: none

Steps to reproduce

1. Create a split view, then select a normal tab
2. Select a view from the Split View and observe the right tab name and icon from the tab bar.

Expected result

• The tab name and icon do not move.

Actual result

• There is a slight movement to the left for the tab name and icon when selected.

Regression range

• Not a regression. Happens with 146.

Additional notes

• Attached a screen recording.
• This may be expected because the Split View tab splitter disappears when the Split View is selected. Please close as invalid if so.

Comment 1

[Sarah Clements [:sclements]]

Hi atrif, is this just for horizontal tabs? I'm not seeing the shift - could you share the video?

Comment 2

[Alexandru Trif, Desktop Test Engineering [:atrif]]

Attachment: move_split

(In reply to Sarah Clements [:sclements] from comment #1)

Hi atrif, is this just for horizontal tabs? I'm not seeing the shift - could you share the video?

Hello! This is for both horizontal and vertical. Sorry for forgetting to add the video. When selecting the Split View, it seems that the YouTube icon and name are brought into focus, and it slightly moves to the left, and when the Split View is not selected, it slightly moves to the right. If more information is needed, please let me know.

Comment 3

[Merci chao]

Oh, it seems the same problem I've reported: bug #2007048

Comment 5

[BugBot [:suhaib / :marco]]

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

For more information, please visit BugBot documentation.

Comment 6

[Bakare]

Hi, can I work on this?

Comment 7

[japandi]

can I get this !

Comment 8

[Bakare]

Attachment: Bug 2006572 - fix right tab name and icon shift when the Split View is selected

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/542346b601e8
https://hg.mozilla.org/integration/autoland/rev/db06243ed5af
fix  right tab name and icon shift when the Split View is selected r=kcochrane

Comment 10

[rperta]

https://hg.mozilla.org/mozilla-central/rev/db06243ed5af