As of version 78.0.3904.70 of Google Chrome, the browser sandboxes itself and thus cannot be grouped - it does not allow Groupy (or any other outside app) to interact with it.
Currently, there is nothing we can do about that. Any complaints should be directed to Google.
Yeah, strike all that. Seems Google backed out of their change.
We will still be putting out a version of Groupy that will compensate should it come back, and for the Brave browser that still seem to have issues, but as of right now Chrome should group.
You may need to reboot your PC as its what I found I had to do on the 4 PCs I tested on.
Stardock Support Manager