We've got a slight inconsistency in our code when a Graphics object is
used after a dispose. The Javadoc comment indicate that the Graphics
object should not be used after a dipose BUT the Class Libraries book
suggests that operations are ignored after a dispose.

The Solaris/X11 code does ignore operations after the dispose and the
Win32 follows this behaviour for some methods. However for the drawPolygon
and drawPolyline methods the Win32 code generates a NullPointerException.

So for example :-

  g.dispose();
  Polygon p = new Polygon();
  p.addPoint( 10, 10 );
  g.drawPolygon( p );

The drawPolyon is ignored on Solaris but generates an exception on Win32.