Thanks. I have a couple more pieces of information to volunteer.
First, the reason I hadn't put this in Feature Requests to begin with is that I'm positive that at least WindowGrid was working at least as recently as 9.1.5. I think I skipped 9.2 and 9.2.5.
Second, despite the fact that I am not running the Visualcron client as an administrator, which is normally what would require this, running WindowGrid or FancyZones as an administrator apparently allows it to affect the Visualcron client window.
While I consider this workaround good to know about, I do not consider it acceptable to rely on without an understanding of why it is necessary...considering that FancyZones in particular only suggests this approach might be necessary for managing elevated windows, and the client is clearly running as my normal user, the fact that this works almost concerns me more than if it didn't.
I know this sometimes results in behavior that is not quite the same as the difference between running as administrator and not running as administrator using the same account, so I will mention that my regular user is not a local administrator on my workstation at all. Running as administrator requires me to use completely separate credentials.