This is indeed an issue in Parallels 7 as well, and came as a horrible surprise after
my fiasco with rotation in OS X.
As a coder who works both in OS X, Windows under Parallels and sometimes in Bootcamp this is a showstopper for me. Had I known the technology would be this flaky I would never have bought a Displaylink monitor.
Please update us on this situation or I will have to start shining light on this issue and discourage others from purchasing Displaylink-enabled products.