2014532 - Ctrl-tab switcher rounded corners display incorrectly with white square corners on macOS

Status: RESOLVED FIXED

(Firefox :: Tabbed Browser, defect)

Description

[Haik Aftandilian [:haik]]

Attachment: Screenshot showing ctrl-tab switcher corner rendering bug

When using the ctrl-tab tab switcher (enabled in Firefox settings with the Ctrl-Tab cycles through tabs in recently used order checkbox), there is a visual glitch causing the rounded corners of the tab switcher to have white square corners. See screenshot.

Edit: this is on macOS 26.2 running the latest Nightly.

Comment 1

[Stephen A Pohl [:spohl]]

This feature has traditionally been tracked in the Tabbed Browser component. Reassigning and blocking meta bug 505404.

Comment 2

[Dão Gottwald [:dao]]

Do you know if this is a regression?

Comment 3

[Haik Aftandilian [:haik]]

(In reply to Dão Gottwald [:dao] from comment #2)

Do you know if this is a regression?

Yes, it's a regression. mozregression got me to https://hg-edge.mozilla.org/mozilla-central/pushloghtml?fromchange=9c6272da5dc92ff944d294d9a026bd42a408c784&tochange=2c44d59dd29eb01ea0b484c9f3f8691861118073 which includes a Mac-specific style change:

Bug 1861671 - Improve macOS non-native menu styling

I see three different appearances going through mozregression:

1. Older non-bug behavior where the gray background shape is rectangular.
2. Bug is less visible because the gray background has a small curve radius.
3. Current behavior where the bug is most visible due to the gray background having a larger curve radius.

@emilio, could this bug be related to your changes in the above regression range?

Comment 4

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2014532 - Override built-in background on ctrlTab-panel. r=haik,#mac-reviewers,#theme

So that we don't use the default panel background on macOS.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/38ff7ccf096b
https://hg.mozilla.org/integration/autoland/rev/dd9862b431f6
Override built-in background on ctrlTab-panel. r=desktop-theme-reviewers,tabbrowser-reviewers,dao

Comment 6

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/dd9862b431f6