I enabled VNC remote administration in Yast because X11 is not stateless. VNC works and I arrive at a desktop but
when I start Yast2 in that desktop, it displays a white window
and
when I close VNC and re-connect, it doesn’t connect me to the existing session but creates a new one (presumably the old session was ended for some reason)
As a workaround, set the environment variable QT_NO_MITSHM to 1, e.g. run YaST like this:
kdesu QT_NO_MITSHM=1 yast2
when I close VNC and re-connect, it doesn’t connect me to the existing session but creates a new one (presumably the old session was ended for some reason)
That’s normal and expected.
If you enable “Remote Administration”, a new X session is started each time you connect via VNC.
If you want to connect to an existing session, run e.g. vncserver inside that session.