C Habbra
xxx: I don't remember how in Windows, and in Mac's after removal works... Yes, Undo. Press Ctrl+Z (or, if more accurate, Cmd+Z) and the file is back in place.
yyy: There is a screw conductor, but only one step back.
xxx: Checked - in the Mac for an infinite number of steps works and Undo and Redo.
Zzz: Have you checked the infinite number of steps? I respect.