When I start an ssh session to my debian testing ("Wheezy") computer,
with "ssh -Y machinename", and start emacs, then exit emacs, and then
then log out, the ssh session hangs on logout.

This happens both when the client is my Ubuntu 10.10 netbook
(openssh-client 1:5.5p1-4ubuntu5), and from a Windows 7 laptop with
Xming, using putty as the SSH client (I don't have the Windows 7
laptop at hand so I am unsure of the exact version numbers).

The problem does not occur if I don't start any X11 applications
during the session.  Then the logout from the ssh session, does not
hang.

The problem does not occur if the machine I connect to is debian
stable.  If try to reproduce the issue with one of my debian stable
machines, ie. log in with "ssh -Y", start an X11 application, stop the
X11 application, and then log out, the session terminates normally.

openssh-server on debian stable is currently at version 1:5.5p1-6.