Comment 54 for bug 1871644

I have just tested the latest nightly on Fedora 35 and it works perfectly for XWayland, however, when running Wayland the bottom corners are still not rounded and the top corners are rounded but still have a weird (barely noticeable unless you know) transparent sharp corner. Note that I am running a [patched version of mutter](https://github.com/yilozt/mutter-rounded) ([RPMs](https://gregor160300.stackstorage.com/s/I4YFXu82ay6mNE0C)) that enables rounded corners in every app, however, Firefox is the only app that breaks the nice uniform look that I believe GTK4/libadwaita are also going for with the rounded corners on all sides (just like Windows 11 and macOS).

I understand that this is an edge case currently (with the patched mutter) but I foresee this becoming a "problem" when in a year or two all other apps also have rounded bottom corners and Firefox is the odd one out, I think fixing this now is a good idea to prevent technical debt.

[Xwayland screenshot](https://i.ibb.co/vw87ST1/Screenshot-from-2021-11-18-12-30-25.png)
[Wayland screenshot](https://i.ibb.co/H7RH0tg/Screenshot-from-2021-11-18-12-30-55.png)
[Other apps screenshot](https://i.ibb.co/R3Xcn4G/Screenshot-from-2021-11-18-12-31-39.png)