This is probably as much a question as anything, probably not a bug at all.
When you make an item selector it shows up over your boomerang, but the "square" you click on to edit it is in the left corner where all new items are created.
Where exactly should that be moved in order for it to be accessible to edit in the future?
Maybe partly over the boomerang?
What was intended when it was designed?
The selector seems to place itself over the boomerang, or item #0 by default, but not the editable square that came with its creation.