There is one way to reproduce this issue.
While Host and guest use same monitor as their primary display, and then configure window7/8 guest to dual-display screen mode, the extended screen for GOS, turn black at once after re-login twice.
If both host and guest use different minitor as his primary display, both screens show the same content (mirrored)for Window 7/8 GOS after logout/login twice.
We have reported one internal ticket to track this issue and thanks a lot for your patience.
If you have other scenario to make this issue happen, please kindly list here and I really appraciate that. your valueable input and criticism are highly welcom and always help us improve Fusion Product.
Thanks you again!
Best Regards,
Changhai