group - new group

i just saw this features in 2.42a

if you click on the object in header you then click on group
you now have choice to make part of existing group or to make new group
or remove from all group:confused:

Why this difference :confused:

is this the way to make sub-group - so when you ungroup you do it at one level only :confused:

Not like the Alt-p which seems to ungroup down to the last level !