What I liked about Gnome in Fedora 7 was user switching. I could lock
my screen, say "switch user", and my relative would log on into his or
her session. I could switch back to my existing session later.

I asked how it could be done with fvwm2, and did not get a very
definitive answer. But I found it out with a lot of ps-ing and
googling.

This does work with fvwm2, as well, and here's how:

Beginning of session: gnome-screensaver &

When locking: gnome-screensaver-command --lock

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