Created attachment 848738 [details]
Troubleshooting Information from the old firefox, that worked (snapshot
20210422)

Hello Everyone,
After upgrading from Tumbleweed snapshot 20210422 to 20210423, the UI in
Firefox is frozen. I tested everything with fresh Firefox profiles too.

While UI is frozen all the time, Firefox still reacts to mouse interactions. I
can switch between tabs and it will change the window title, but not the
content of the window itself.

The problem goes away, when:
a) I disable hardware acceleration in Firefox.
or
b) I disable display compositing on xfce. But xfce wasn't upgraded with this
snapshot AFAIK.

DE: xfce