Are you using a display manager other than tdm? On
some machines I use
lightdm, and the option to switch users without logging out is not available.
Nope, I use purely TDE. The option is in the kicker menu, so the dm in use should not
matter. The menu of the session
could though, in case you are not running a TDE session but using TDE program inside a
different session :-)
Cheers
Michele