2008756 - Split view's focus-outline is clipped on the right side of left tab

Status: RESOLVED FIXED

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

Description

[Daniel Holbert [:dholbert]]

Attachment: screenshot

STR:

1. Open two copies of https://example.org/ in split-view. (or any website will do)
2. Focus the left tab and look at the focus outline that surrounds it.

ACTUAL RESULTS:
The right (center-most) edge of the focus outline is missing/clipped.

EXPECTED RESULTS:
No such missing focus-outline.

If I focus the right tab instead, then it gets fully surrounded with a focus outline.

I'm using Nightly 148.0a1 2026-01-06 on Ubuntu 25.04

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: screenshot more zoomed in, showing focus outline on top but not on the right edge (center divider line)

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: reference scfreenshot showing full focus outline around right half (good/expected)

Comment 3

[Sarah Clements [:sclements]]

Do you see this on windows too or just linux?

Comment 4

[Merci chao]

Attachment: Clipboarder.2026.02.06.png

(In reply to Sarah Clements [:sclements] from comment #3)

Do you see this on windows too or just linux?

Also happens on Windows.

Comment 5

[Merci chao]

Attachment: 2026_02_06_10_38_05.mp4

Actually, the outline of the unselected panel is also clipped. You can see four rounded corners left behind, which look strange.

Comment 6

[Daniel Holbert [:dholbert]]

(In reply to Sarah Clements [:sclements] from comment #3)

Do you see this on windows too or just linux?

Windows too, yes (confirming comment 4). Doesn't reproduce for me on macOS, though.

Comment 7

[EJiro Oghenekome]

Hi can i work on this

Comment 8

[japandi]

assign me please

Comment 9

[EJiro Oghenekome]

I am working on this

Comment 11

[Keji Bakare]

Hi, why am I being unassigned…I already worked on it and just about to add a patch

Comment 12

[Nikki Sharpley (:nikkis) (she/her)]

Oh my gosh, I am so sorry for the mix up. Carry on, Keji, its still yours!

Comment 13

[Keji Bakare]

Attachment: Bug 2008756 - fix Split view's focus-outline clipped on the right side of left tab

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/22a001cca781
https://hg.mozilla.org/integration/autoland/rev/9e853f018e2f
fix Split view's focus-outline clipped on the right side of left tab r=nsharpley

Comment 15

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/9e853f018e2f