Each morph (except for the world itself) is owned by exactly one other morph. This is the morph's property owner. If the owner is null,then the owner is the world itself.
You can see the owner of a morph by asking for its owner property, like this:
$morph('SmallEllipse').owner
which gives us a string.
Fortunately you can get a morph to show itself. Try cmd-d on:
$morph('SmallEllipse').owner.show()
which shows little red corners on the small rectangle
you can also do:
$morph('SmallEllipse').owner.owner.show()