I'd also like to see a Groupy created context menu item, "Open in New Tab".
I thought last summer, while in a File Explorer grouping; I'd select a folder, select open in new window; and the folder would open in a new window than that window would join the existing group. This seems to have changed sometime this fall.
Now, the new window does not join the existing group automatically. I go back to the the original group and add it to the newly opened window. I don't see where any of my Groupy settings have changed.
I'm using Groupy v1.25 on Windows 10 1903 on both my PC and laptop.