The problem is that the flood fill that fills the "outside" messes up when the outline touches the edge of the workspace - it ends up flood filling the inside as well. If you grow the workspace a bit and move the board away from the edge, it should work OK.
The problem is that the flood fill that fills the "outside" messes up when the outline touches the edge of the workspace - it ends up flood filling the inside as well. If you grow the workspace a bit and move the board away from the edge, it should work OK.