Deleting a Property from a Model should be more thorough

(User Story, To be Fixed , Priority: Medium, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Editor, Properties
Summary: When I delete a Property from a Model, 3 times out of 4, I don't need that Property at all any more. But truly deleting it is a pain: I have to Show all Properties, go to the Property itself, and delete it manually. This should be easier.
When I delete a Property from a Model, check whether it is used elsewhere. If it is used only by Instances of this Model, offer to delete from the Instances and delete the Property (warning that data will be lost!). If it isn’t used anywhere else, offer to delete the Property entirely -- that's usually what you want.