05 Aug 2017 12:54
Yes, I did follow the instructions carefully.
In the HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers registry key, I put C:\VPC\VPC.EXE in the value name where I installed Virtual PC and added NoDTToDITMouseBatch string value.
The reason why I renamed the executable, "Virtual PC.exe" to "VPC.EXE" is due to compatibility issues with Windows 8.1.
I did apply the KB2903939 patch, but it still didn't solve the mouse stuttering issue when capturing the mouse cursor inside the windowed VM on the secondary monitor.
15 Aug 2017 05:46
Okay, this does not seem to be a issue with the second monitor, but more of a text and item resizing issue.
If I set the screen resolution on my second monitor to either 1280 x 1024 or 1600 x 900, the mouse inside the virtual machine's guest operating system does not stutter.
However, if I set the screen resolution to either 1600 x 1024 or 1600 x 1200, the mouse stutters!
But I found another way and I solved the problem! How I did it?
Go to Control Panel, select Appearance and Personalization and go to Display.
Click on where it says, "Make text and other items larger or smaller".
You will see the section that says, "Change the size of all items", click on Smaller - 100% (default) and check mark "Let me choose one scaling level for all my displays". When you're done, click on Apply.
You will need to sign-out of your local account or Microsoft account in order for the changes to take effect.
I hope that this solves the mouse stuttering problem!