There are many questions like this already, but non for the actual FF4 release. When I close FF4 I lose all my tab groups. If I tell FF to open previously opened tabs, it saves the tabs & tab groups of the '''most recently closed FF4 window'''. This means that if I have 2 FF windows open and I close the one that has all of my favorite tabs, I've just lost everything. I'm sure there is a setting somewhere to "bake" or set basic tab groups. (perhaps a folder that I could bookmark my defaults to?) I really don't want to have to install an add on to make tab groups useful.