Hotspot history
Ten automatic snapshots, and an undoable restore.
Every time you save an interactive image, PixMapr snapshots its hotspots and styles first, keeping the last ten versions.
If an area is removed by mistake, restore it from the Hotspot History box on the edit screen. Restoring is itself undoable: the version you replace is kept too, so you can step back and forward until the image is right.