Issue: If you start Cubase first and then add a second monitor(screen), menus disappear. That is, you can still use them, but you only see them if you go to the “blank” menu bar and click where you think they are. They are there, just invisible.
Everything else runs ok until you close the window/project you are working on, or try to get back to another window with an inactive project. Cubase either becomes invisible (that is, it is still running, but you cannot see it), or you cannot do anything, except keyboard commands. You have to basically force-quit and restart. You can still save with a keyboard command, but that is about it.
If you on the other hand start all your monitors/screens before you start cubase there is no problem at all.
Anyone else having this issue? Using more than one screen in cubase is extremely handy and quite important that it works well, and sometimes you forget to turn on the second monitor before running cubase… 
Sure, the solution is to make sure you turn on the monitor first, but it seems to be a Cubase hickup.
I’m running Windows 10, 64 bit which is running very smoothly for me, both in terms as an OS, and running Cubase 8 Pro. Also, it seems like the OS handles dual monitors way better than previous OSs.
I am running the latest drivers on all.