How does "Cycle Through (Subselect) selected Units" work?

Does anyone know how this menu option works? I’ve tried it in several ways, but I can’t understand how this option works. When I have a group of units or buildings in 1 only group and press Tab to subselect them nothing happens, it doesn’t center as informed.


Sorry to revive this topic, but I’ve searched and this is the only thing I can find regarding this menu option. Did you find an answer @cienlo?