Paint a representation of the value into a given area of screen real estate. Note that the propertyEditor is responsible for doing its own clipping so that it fits into the given rectangle.
If the PropertyEditor doesn't honor paint requests (see isPaintable) this method should be a silent noop.
The given Graphics object will have the default font, color, etc of the parent container. The PropertyEditor may change graphics attributes such as font and color and doesn't need to restore the old values.
@param gfx Graphics object to paint into.
@param box Rectangle within graphics object into which we should paint.