hidden processes / nautilus, gnome-vfs-daemon

[Michael Schwendt <ms-nospam-0306 arcor de>]

On my FC2 Test2 installation, there are four hidden processes. Three are
nautilus, one is gnome-vfs-daemon. Their PID directories below /proc are
hidden, and the processes cannot seem to be listed with "ps" either.

What exactly is the reason for hiding them?

I've failed to find something about it in the nautilus changelog.