I don’t know what the problem might be. I and about 10 others near me use Paratext in Windows VMs running in Parallels, VMware, or Virtualbox on a Mac. I haven’t seen a scrolling problem such as you describe. I use the latest versions of each, but others have many other combinations.
Parallels Desktop 11 and 12 were released with Windows 10 support, but Parallels Desktop 10 received an update which provided support for the Windows 10 Technical preview and I’ve heard reports of people using Windows 10 under Parallels Desktop 9 as well.
The virtual machine settings can be adjusted to enable/disable “Smooth scrolling” or to “Optimize the mouse for games.” Perhaps one of those settings would fix the problem.
They should also confirm that the Parallels Tools are properly installed (on the “Actions" menu). This will replace the native drivers for the display, mouse, and audio with Parallels-provided drivers.
Since none of those answers seem very helpful to me, and I thought it’d be fun, I set my Windows 10 display language to Hebrew. With the Windows 10 display language set to Hebrew, the Paratext 7.5 menus often open as completely black rectangles, the chapter selector buttons disappear, text disappears from the drop-down lists, Bible text disappears or moves around. The program is unusable. With difficulty, I submitted a problem report.
I tried Paratext 8 and Paratext 7.6 and didn’t see a problem. So I opened Paratext 7.5 again and couldn’t reproduce the problems. I restarted the VM and Paratext 7.5 still works perfectly.
Now, can somebody tell me how to change the display language back to English?
LivingField