Groups in Z-A order

Hi, my groups have sorted into Z-A order and I don’t know how to get them back to A-Z? Please help. 

Not easy or obvious but the little ^ (a-z) or v (z-a) at the top of the groups window sorts them.  

I couldn’t figure this out for a while and then discovered if I clicked on “My Library” at the top of the groups window, it switched back and forth between A-Z, Z-A…!