Groupy can group any window that has a title bar which is what all apps should have if they are normal windows.

I wouldn't be surprised if those apps were built with the buggy version of the Electron framework that got released last year.  It was fixed but some devs may not have updated to the new framework.

End result is the apps have no title bar set so are ignored by Groupy as look the same as splash screens to Groupy.

This is something the developers of those apps really need to fix by upgrading to the fixed releases of the framework.