I thoroughly investigated the issue this user is having and cannot duplicate it. The skin has been around for many years and was only updated recently. No one has ever reported an issue like this, so there is really nothing I can do. I gave him this information in a PM he sent me also.

I am using Win10 V20H2 (OS Build 19042.870) and WindowBlinds 10.86 (061 - Windows 10 Edition) - 64 bit OS right now. When I worked on the update of Sensua I was on Windowblinds 10.84 though and I also use Old New Explorer.

The Sensua skin worked perfectly in all cases, but I found what is causing these issues.

Any skin that uses UIS2 frames only has these issues without Old New Explorer installed, so I had no idea there even was an issue. If I apply any skin that uses UIS2 frames only I see these issues, so therefore this is a Stardock problem and not mine. Hope they can fix it.

As additional data - Maybe it matters if Old New Explorer has ever been installed?  It's never been  installed on this machine, as far as I can tell Sensua is fine:

Indeed, that did it

Thanks for fixing the issue so quickly!