Opening tabs sidebar in fullscreen breaks browser UI on macOS

[AmigaEnjoyer]

What happened?

When entering fullscreen mode on macOS with the tabs sidebar enabled or when enabling it when in fullscreen mode it causes the the browser UI to become squished and sometimes the tabs sidebar does not appear. The images show before and after entering fullscreen mode with the sidebar enabled. This is the extension that comes with Waterfox and not a separate one.

Reproducible?

• I have checked that this issue cannot be reproduced on Mozilla Firefox.

Version

G6

What platform are you seeing the problem on?

macOS

Relevant log output