I've noticed while working on site updates for a client's live site:
I can make edits to pages within Designer and not publish. Then, if my client were to go into Editor and create a post (or any other changes) and they publish their edits, my edits get pushed to the live site as well.
It would be nice to have a way to control what gets published between Designer and Editor. I imagine it might be simpler to have an entirely separate "staging site" as opposed to selecting individual pieces or elements to publish. You guys are the experts though. ; ]