XEmacs on WinXP with Virtual Desktops

Hi all,

I'm having a very annoying problem with XEmacs 21.4.15 on WinXP
when using a virtual desktop manager (I tried DesktopTwister and
goScreen4 - both give the same effect).

When I leave the virtual desktop with the XEmacs and then come
back, it does redraw the window and it's contents, but I cannot enter
anything anymore. If I drag the scroll bar it doesn't scroll the buffer
and it jumps back to where it was, when I release it. I can execute
commands from the drop down menu and switch between buffers
using the taps, but the buffer contents remains the same.
Only when I resize the XEmacs window, the blockage dissappears.
But this is not a good workaround, because I often switch desktops.

This effect only occurs with XEmacs, all other applications just work
fine:-((

Any ideas? This was not there on Win2000 - it's only on XP!

Thanks for any help!
Gerhard Petrowitsch