I tried:
sudo apt-get install -y xdg-desktop-portal
It didn't cure the problem, right after install. Re-installed firefox didn't make it work either. After reboot everything was working.
Question is, where did I loose this xdg-desktop-portal, but I'm quite sure it wasn't there from the initial install, because I see the same behaviour on some other test system.
I tried:
sudo apt-get install -y xdg-desktop-portal
It didn't cure the problem, right after install. Re-installed firefox didn't make it work either. After reboot everything was working.
Question is, where did I loose this xdg-desktop-portal, but I'm quite sure it wasn't there from the initial install, because I see the same behaviour on some other test system.