I have been (successfully) using XWin with -multimonitor -multiwindow recently. However, since upgrading to the latest release (via setup.exe - 4.2.0-3)
4.2.0-3 of what? The only really useful version number is the version of the XFree86-xserv package, and the current version is 4.3.0-49. Update tomorrow and see how it works.
Harold