Back in the F36 Branched VM, i did the latest batch of updates & rebooted, then decided to log into its GNOME [rather than KDE] Wayland desktop first. Fired up V from terminal with vivaldi-stable --enable-features=UseOzonePlatform --ozone-platform=wayland. Once the proper V window appeared, it seemed to behave fine. In its vivaldi://gpu:
XDG_SESSION_TYPE wayland
Ozone platform wayland
Logged out of GNOME, logged into Plasma Wayland, launched V again from terminal, & it seems fine. In its vivaldi://gpu:
XDG_SESSION_TYPE wayland
Ozone platform wayland
NB: Not in my GNOME login, only in my KDE login today, my initial attempt to launch V once again resulted in the V processes appearing, & the V icon appearing in the Plasma Panel Task Manager, but no actual V window. Confused, i eventually realised my mistake; i'm so used to Arch that i forgot that whereas in Arch V Stable launch command is simply vivaldi, whereas in Fedora it must be vivaldi-stable. I got it right when i was in GNOME, but slipped up initially once in Plasma. It transpires that when launched only as vivaldi in KF-W, the window is not created, but once correctly launched, all is good.
I now strongly suspect that i made this same silly error in yesterday's F35 test, so am about to try that again...
F35 tba... --> upon initial relaunch today of my F35 Stable VM, i verified that in fact i had NOT made a launch command error; i had indeed used vivaldi-stable --enable-features=UseOzonePlatform --ozone-platform=wayland ... & again today the V window did not appear.
Then, i found that 22 packages were available for update, including several fedora wayland library packages. I applied the updates, logged out/in, repeated the launch command... & voila, V is good! In its vivaldi://gpu:
XDG_SESSION_TYPE wayland
Ozone platform wayland
So, it had been a Fedora problem, not a V problem. With that resolved, F35's V-W behaviour is normal, no menu or other hassles experienced.