final VisualizationViewer vv = app.getVv();
vv.setLayout(new BorderLayout());
vv.setBackground(Color.white);
// add a mouse listener to manage mouse event on graph element
vv.setPickSupport(new ShapePickSupport(5));
vv.addMouseListener(new XGrapherMouseListener(app, vv, mapper));
vv.setGraphMouse(app.getModalGraphMouse());
this.add(vv, BorderLayout.CENTER);
}