Problem with Xemacs and cygwin and maybe XP

I have a problem with the interface between Xemacs and cygwin (and maybe
XP).

I recently updated my cygwin distribution.  Now whenever I do anything
that starts a new shell on Xemacs the screen fails to refresh.

Examples include trying to LaTeX a document using auctex, start R (the
statistics program) using ESS, and start a shell using M-x shell.

Xemacs still responds to commands (I can quit using C-x C-c), but it
loses all ability to write to the screen.  For example, if I cover
Xemacs with another window, then remove the window, all I see is white
space in the area I covered.   

I'm running Windows XP
Xemacs 21.4, april 2001 (the "cygwin" version installed with the windows
installer "install now")
My cygwin distribution is current as of today.

I have two XP computers and I have the same problem on both of them.  I
have third win2000 computer, but I'm scared to update cygwin on it just
to see if the operating system is part of the problem.  

Steve