We have noticed severe problems with X11 under SL 4.0 here. The problems 
mostly occur when we open windows on a remote machine and display them on a 
machine running SL 4.0. The remote machine can be both another 4.0 machine or an 
SL 3.03 machine, the problems are the same, suggesting it is a feature of the 
X11 server. I note that the X11 system is now xorg-x11, not xfree86 as before, 
and I can't help but suspect this is the culprit. Here is a list of the problems 
we have encountered:

1) Complete system hangs when closing windows. These are rather random and hard 
to reproduce, but we have definitely seen them. ( No remote machine involved in 
this case)

2) secure shell to a remote machine with x forwarding enabled:

  emacs - click in the window to edit, sooner or later it crashes saying:
=======
     X protocol error: BadWindow ( invalid window parameter ) on protocol request 38

  root
======

     opens up, and throws up the splash window ok, but gets an error
Error in <RootX11ErrorHandler>: BadAtom (invalid Atom parameter) (XID: 39, XREQ: 18)

  then when trying to create a browser it says

TBrowser a;
Error in <RootX11ErrorHandler>: BadAccess (attempt to access private resource 
denied) (XID: 64, XREQ: 102)

  we posted a message to the root people and got a suggested solution but it did 
not work.

3) Trying to avoid the ssh tunneling route does not work at all:

    export DISPLAY=blah:0.0

    on blah: xhost +

   just does not work.



  I realise these problems can not be solved by the Scientific Linux community 
as they are not the authors, but I suspect our community may do this sort of 
thing more often and so be more aware of it. Have other people seen it? Can it 
be fixed?

             Alex Finch