ssh and X display

[Tomasz Kosinski <mickle@escape.com>]

Until an "apt-get dist-upgrade" a few days ago, I have used ssh to log
in to the computer while another user is running an xsession:

        "ssh -l username localhost" in an xterm has always enabled one
        user to log in to another users Xsession and use one of the
        virtual terminal/desktop/workstations to run x apps (from the
        command line) while the original user is running his x apps
        (from menu).

        "ssh -l username 127.0.0.1" in an xterm would allow a second
        user to log in but not to run x apps.

After update, I can no longer run x apps when sshed into localhost. X
forwarding is turned on, from sshd_config:

        X11Forwarding yes
        X11DisplayOffset 10

I don't need the security of ssh, I just need two different users to be
running x apps on the same computer, during the same xsession.

Any help (for a SIMPLE END USER) will be very much appreciated. Thanks,

Tomasz