The main config in ~/.fvwm/ is .fvwm2rc or config
From the FAQ:
So open the config in an editor mark all and paste it between the code tags.
To change it to a single desk search for
DeskTopSize
and change it to
DeskTopSize 1x1
Another thing you can do to stop switching is, search for
EdgeScroll
and change it to
EdgeScroll 0 0
Hmm, don’t know how VNC have to be configured. I don’t use it. So can’t help.
Part of Archwiki about .Xdefaults:
So this file is used for x applications and the behaviour of the x-server not for a window manager.