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[Bug] Custom browser theme breaks listening to system color scheme (Firefox, Linux)

See original GitHub issue

Bug Report

Bug Description

When Change the browser theme (More tab) is set to Custom and automation is set to Use system color scheme, the extension switches on but not off on system theme change.

Steps To Reproduce

Start a fresh profile and install Dark Reader.
Turn extension on and set Change the browser theme (More tab) to Custom; turn extension off again.
Set Automation (kebab menu) to Use system color scheme.
Switch system dark mode on.
Switch system dark mode off.

Expected Behavior

The extension turns on and then off on steps 4, 5.

Actual Behavior

The extension does turn on but remains so after switching the system to light mode again.

System Information

OS: Manjaro 21.2.0 with i3wm (using xsettingsd to switch between Adwaita and Adwaita-dark)
Browser: Firefox 95.0
Dark Reader Version: 4.9.43

Additional Context

The bug appears to have surfaced with the upgrade to Firefox 95.0. I tried it with 91.4.0esr and could not reproduce it.

Issue Analytics

State:
Created 2 years ago
Reactions:5
Comments:10 (4 by maintainers)

Top GitHub Comments

2reactions

adqlcommented, Dec 13, 2021

Update: when changing the about:config property layout.css.prefers-color-scheme.content-override to 2 (system) the bug is “solved” (but not actually resolved), which confirms the context of the recent Firefox change behind this. Here adding a UI element to change this property is discussed.

This property’s value can be 0 dark, 1 light, 2 system or 3 browser. When Dark Reader is set to Use system color scheme automation and to overriding the browser theme with Custom, this only works as expected when layout.css.prefers-color-scheme.content-override is set to 2 (system). On 0 (dark) and 1 (light) dark reader remains always on or off respectively. On 3 (browser), which is default since 95.0, the behavior originally described in this issue is reproduced (unidirectional switch off > on).

It seems likely that Dark Reader both relying on prefers-color-scheme and modifying the browser theme leads to a “lock” in the case of option 3, where it can turn itself on but then not off since it keeps the theme dark… I don’t really know about its internal design but I guess it should somehow rely directly on the system theme, regardless of the setting for websites. Is it at all possible?

1reaction

alexislefebvrecommented, Dec 16, 2021

Thanks adql, it looks like setting layout.css.prefers-color-scheme.content-override to 2 fixed the issue.

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