We recently upgraded to a new PC Windows 10 and EW7. All went well and thank you for tech support help. We have 3 extended displays - 2 for the audience and the 3rd is the PC monitor. When running EW the mouse will disappear off the left of the PC monitor screen. We then just drag the mouse itself to the right for the mouse arrow to reappear on the screen.
I have reviewed forums for Microsoft and yours and have found nothing specific to this. I did find on another forum about installing a 3rd party tool but not sure this is a viable option.