P: (Lens Blur) Add more focused objects

Right now there's a single automatic "subject" selection for the focal range. Any surface I want to add is manual, using brushing, which is tedious and inaccurate. It would be nice to be able to point at other objects and have the AI detect them and add/replace them as the focus surface. Add is even more important than replace, because selecting a person as the initial focal surface is usually appropriate, but fixing errors around the subject person is difficult at the moment.