1524279 - ui.-moz-win-accentcolor not respected

Status: UNCONFIRMED

(Core :: Widget: Win32, defect, P3)

Description

[Steven Noonan]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0

Steps to reproduce:

1. Use the "Dark" theme that comes with Firefox
2. Enable "Show the accent color on the following surfaces: Title bars and window borders" in Windows settings and pick an arbitrary accent color.
3. Set about:config option ui.-moz-win-accentcolor to #000000.
4. Alt-tab away and back. Observe that the color set in about:config is respected, making the dark theme actually dark.
5. Change accent color in Windows Settings, or toggle the "Show the accent color on the following surfaces: Title bars and window borders" option a couple times.
6. Firefox no longer respects ui.-moz-win-accentcolor and uses the globally set Windows accent color, until the about:config value is changed to something else (e.g. the functionally equivalent #000 would restore the black accent).

Actual results:

Firefox will sporadically stop respecting ui.-moz-win-accentcolor. It's not clear what other circumstances cause it to use the global Windows setting again, though one clear repro is provided above.

Expected results:

I would expect ui.-moz-win-accentcolor to override the Windows accent color 100% of the time.

What I really want is some option to just make Firefox ignore the Windows accent color, because I like the dark theme. I thought ui.-moz-win-accentcolor would be sufficient. I really don't want to globally turn off the "Show the accent color on the following surfaces: Title bars and window borders" option just to preserve the black accent color. The Windows global setting looks fine on most apps, but violates my intent to use the dark theme on Firefox.