Searching through previous posts, it's pretty clear, that Firefox has had problems with Groupy for some time. While, I find that Firefox windows can be grouped using Groupy without issue, if you then save that group, and reload it, it will open a Firefox window, but it won't load it into the group, it just opens it separately, and you have to drag and re-add it to the group. Better than it not working at all, but mildly annoying.
