I was able to reproduce the window issue on Firefox 87.0b5 wayland session under Ubuntu 20.04 by following the info provided in Comment 0.
The issue is fixed and the indicator appeared on the left side of the screen on Firefox 90.0b5 on the same system.
I was able to reproduce the window issue on Firefox 87.0b5 wayland session under Ubuntu 20.04 by following the info provided in Comment 0.
The issue is fixed and the indicator appeared on the left side of the screen on Firefox 90.0b5 on the same system.