Trivial question :)
When I name
Sphere = ob1
Cube = ob2
Selection ob1 + ob2 and name it = ob3

Now when I select the Sphere only, Sphere's name is ob3, Cube's name only selected is ob3
How clear the group selection? (ungroup)

And seems the Undo to the start keeps the all group name ob3!

if I select all so ob3, when I clear the the name ob3
Sphere and cube become Unnamed !!! seems must be ob1 and ob2 ;)

PS there is not yet a list ?...(arborescence)...