1950071 - Mixed light and dark theme colours intermittently

Status: NEW

(Fenix :: Design System and Theming, defect)

Description

[Marcin Koziński]

I know this has been already reported a bunch of times. But some of these bugs have been closed as fixed and it just happened for me a few times in the last few days on the latest Nightly, so wanted to open a fresh bug.

Steps to reproduce

Unfortunately I don't have deterministic steps to reproduce. It's intermittent and "just happens sometimes" during normal daily usage. But the gist is:

1. Set Fenix to follow system theme (unsure if this is a requirement, maybe this can happen with manual theme changes between light and dark within Fenix).
2. Set system dark theme to change at sunrise and sunset.
3. Use Fenix multiple times a day, before and after system theme changes.

Expected behavior

Fenix uses a consistent theme, synced with the system theme.

Actual behavior

Intermittently Fenix's UI uses an inconsistent mix of dark and light theme colours, with some parts of the UI using light backgrounds, some dark backgrounds and even some displaying light text on light background or dark text on dark background. See screenshots.

Device information

• Firefox version:
  • 137.0a1 (Build #2016074623), hg-f47117ef97a7+
  • GV: 137.0a1-20250218205441
  • AS: 137.20250208050325
• Android device model: Pixel 9
• Android OS version: Android 15, build AP4A.250205.002

Any additional information?

Comment 1

[Marcin Koziński]

Attachment: 1000003484.png

Comment 2

[Marcin Koziński]

Attachment: 1000003486.png

Comment 3

[Marcin Koziński]

Attachment: 1000003483.png

Comment 4

[Marcin Koziński]

Attachment: 1000003481.png

Comment 5

[Marcin Koziński]

Attachment: 1000003510.png

Comment 6

[Marcin Koziński]

Attachment: 1000003511.png

Comment 7

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

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

For more information, please visit BugBot documentation.

Comment 8

[Marcin Koziński]

Attachment: Device switched to dark mode. Correct: status bar background in dark. Incorrect: status bar text (dark on dark), tab tray, address bar in light.

Happened again this weekend.

Device information

• Firefox version:
  • 138.0a1 (Build #2016077607), hg-29ca7ddfb776+
  • GV: 138.0a1-20250306092841
  • AS: 138.20250305050254
  • 2025-03-06T12:24:05.692057384
• Android device model: Pixel 9
• Android OS version: Android 15, build AP4A.250205.002