Terminal: Dark titlebar in classic CMD is broken in Insider builds

[sylveon]

Environment

Windows build number: 10.0.18985.1 (Sorry for being outdated, I haven't been able to update to a more recent Insider build)
Windows Terminal version (if applicable): N/A

Any other software? No

Steps to reproduce

Open cmd.exe compiled from this repo or built in Windows.

Expected behavior

The titlebar is black, like in the current stable Windows.

Actual behavior

The titlebar isn't black:

[sylveon]

The window is active in this screenshot

[DHowett-MSFT]

Funny enough -- you filed this shortly after I saw an uptick in log entries (in a local dev build) about this API failing. Thanks!

[sylveon]

The API used is technically undocumented and got moved to WCA_USEDARKMODECOLORS in the also undocumented SetWindowCompositionAttribute API, IIRC.

IMO it should be documented, because other apps might also want a dark titlebar, especially if they have a built-in dark theme because the white titlebar becomes an eye sore.

[DHowett-MSFT]

Hey! The fix for this went out in Windows in the Insider channel's Fast Ring with build 19013.

[raddinet]

The API used is technically undocumented and got moved to WCA_USEDARKMODECOLORS in the also undocumented SetWindowCompositionAttribute API, IIRC.

Thank you! Can confirm that such change works.

IMO it should be documented, because other apps might also want a dark titlebar, especially if they have a built-in dark theme because the white titlebar becomes an eye sore.

Exactly.

[DHowett-MSFT]

We don't disagree with you.

[sylveon]

Finally got to update my insider build after windows update kept refusing, can confirm it works (third party apps are still broken so they'll have to move to SetWindowCompositionAttribute).

The code here also hasn't been updated https://github.com/microsoft/terminal/blob/9b92986b49bed8cc41fde4d6ef080921c41e6d9e/src/interactivity/win32/windowtheme.cpp#L47