Another problem with the tab groups in Firefox, is that resizing the window while the tab group expo is open will "rearrange" the tab groups to fit into the win

Another problem with the tab groups in Firefox, is that resizing the window while the tab group expo is open will "rearrange" the tab groups to fit into the window, and won't remember where they were when you resize it back. It's a complete waste of time trying to spatially organize your groups because FireFox knows better.