Hello,
this behaviour might be due to different things and it’s not the first time it pops up.
Please, see my post here: http://www.steinberg.net/forums/viewtopic.php?f=196&t=53066&start=25#p332290
This is also an interesting, possibly useful, albeit long read: http://www.steinberg.net/forums/viewtopic.php?f=196&t=54815 - there are some tips discussed, including changing the mouse behaviour which helped various users (http://www.steinberg.net/forums/viewtopic.php?f=196&t=54815&start=50#p341713).
Most probably a GPU / software interaction, but these issues can be sometimes caused by performance. As a broader approach, please see my post here: http://www.steinberg.net/forums/viewtopic.php?f=230&t=71314&start=75#p424868.
Waves is working fine for most Cubase users, so I’m pretty sure you can get this sorted. This means the thread does not belong in this sub-forum, I’ll move this thread to Issues → Miscellaneous later on - you can also get more replies as posting there does not require approval.