code: public void drawMapRectangle() {
  		mapWidget.getVectorContext().drawRectangle(group, MAP_AREA, 
  				new Bbox(0, 0, mapWidget.getWidth(), mapWidget.getHeight()), 
  				// IE9 does not draw an empty shapestyle (new ShapeStyle()), but it does draw one with opacity = 0...
  				new ShapeStyle("#00FF00", 0, "#00FF00", 0, 1));
  //				new ShapeStyle("#00FF00", 0.1f, "#00FF00", 0.5f, 1));
  	}
docs: Provides a rectangle over the map, on which the onDrag event of {@link ZoomSliderController} is listening.
  An onUp event redraws this rectangle into the start rectangle with {@link SliderArea#drawStartRectangle()}.