Window controls are missing on Windows

🐞 Bug Report

Screenshot

Reproduction steps

Open Tor Browser alpha after the recent update.

Expected behaviour

No missing symbols.

Actual behaviour

Missing symbols.

User impact

Sad user.

Bookkeeping

  • Browser version: 16.0a1
  • Browser channel:
    • Release
    • Alpha
    • Nightly
  • Distribution method:
    • Installer/archive from torproject.org
    • tor-browser-launcher
    • homebrew
    • other (please specify):
  • Operating System:
    • Windows
      • Version: 11 Pro 25H2
    • macOS
      • Version:
    • Linux
      • Distribution + Version:
      • Desktop Environment + Version:
    • Android
      • Version:
      • Device:
    • Tails
    • Other (please specify):

Browser UI language

Have you modified any of the settings in about:preferences or about:config? If yes, which ones?

No.

Do you have any extra extensions installed?

No.

Troubleshooting

Close and reopen doesn't fix it. Reboot doesn't fix it.

Does this bug occur in a fresh installation?

I don't know.

Is this bug new? If it is a regression, in which version of the browser did this bug first appear?

I don't think it was already present in the previous alpha version but i am not sure.

Does this bug occur in the Alpha release channel?

Yes.

Does this bug occur in Firefox ESR (Desktop only)?

I don't know.

Does this bug occur in Firefox Rapid Release?

No.