I had purchased Groupy, but it just didn't work.
I tried it on the simple windows, like Notepad or Windows File Explorer. But there is just no tab on the window, and the windows won't group together. I don't see any problem in the Groupy settings, it's just not working.
I also tried purge and re-install Groupy, still the same result.
I'm using the latest version of Groupy and Windows 10 20H2 build 19042.1110