Hello, recently started using group tabs v143 - very cool!

One thing I noticed is that when I close all the ungrouped tabs I was just using, FF will then open one of the grouped tabs. I assume this was the last grouped tab I used, which may not be today, and not what I want to do right now. Is there a way to have FF not go into a group after that last ungrouped tab was closed - maybe just open a new blank tab or homepage? If not possible now, where do I add this to a feature/setting wishlist? Cheers!