It would be good to be able to select an internal boundary/polygon to exclude from an area for hatching/shading or doing area calculations. For example if you have a driveway or road with a roundabout, garden or island in the centre; to be able to exclude that area from the external polygon hatching so only the pavement area is hatched.
It would also be nice to be able to turn off (make unelectable) the centre of a polygon/boundary of an unfilled polygon so when working inside the boundary of the polygon it is not selectable.