I would guess that it is impossible to test a software on every conceivable rig/setup.
It is Windows 10, with a Nvidia add-in card, running on the driver version specified in my Stardock support tool output, with >1 monitor. That can't possibly take more than 20 minutes to replicate. Whether you call it a Stardock issue or a Nvidia issue - it's behavior exhibited by the Stardock software, which puts the ball firmly in their court.
What's confusing to me is that after all MY effort (many hours total now), someone at Stardock can't take that 20 minutes and try replicating it themselves. I'm not a Stardock employee - saving money by making me jump through endless hoops is only okay for so long.
IF there's a bug with the Nvidia driver software and Fences, do you think it's the software developer's responsibility to resolve it, or the end-user? I can tell you - it's not the end-user. When game designers have driver issues, THEY work it out with the company who made the driver. They don't tell thousands of end-users to contact the driver company and get it resolved.
This bug basically affects anyone running W10 with Nvidia and >1 monitor, where Fences and Deskscapes are installed.
Over three months it's been myself and two Stardock people trying to find fault in my system, or it's configuration. I think I've done enough leg work there - Stardock can replicate the issue on their hardware now, determine that the bug exists, contact Nvidia, and get it slated for being addressed. The fact it sat, unaddressed for as long as it did, is distressing to say the least.