I like working in full-screen when working in InDesign on my Mac. Is that not supported?
It's been a while since I used a Mac, so someone else may have better info, but look into activating the Application Frame.
Yeah, that's activated but it's not what I'm wanting to do. I want to be able to get InDesign to expand to a new screen like all other apps do.
No. InDesign doesn't have that option. The menu bar/title bar will always be visible on a Mac.