jarle@uninett.no (and others, with the same content):
> Yes.  "X11 Security extensions" is the culprit.  Take a look at
> the -Y flag in the ssh client manual page, or possibly the
> ForwardX11Trusted directive the the ssh_config(5) page.

Ah. Works. Thank you, Jarle and others, who all pointed this out to me.

Would it too much asking that somone with the right clue and CVS bits
inject some code, so that ssh produces an error message that is
slightly more informative than the

  X protocol error: BadWindow (invalid Window parameter) on protocol
  request 38

one gets from the X11 application on the remote side? *PLEASE*!?

How about: "Untrusted X11 client terminated. See ssh -Y flag." in the
ssh client end? Yes I understand that there are problems with the fact
that the X application doesn't have a direct relationship with SSH,
but still - ssh terminates the X11 session, so it should be able to
say _something_ useful on the local ssh stderr. I am neither the
first, nor will I be the last user to drive into this deceptive fog
bank.

				Cheers,
				  /Liman