*/
protected void configureGraphicalViewer() {
super.configureGraphicalViewer();
GraphicalViewer viewer = getGraphicalViewer();
viewer.getControl().setBackground( ColorConstants.white );
viewer.setEditPartFactory( new VertexEditPartFactory() );
viewer.setRootEditPart( rootEditPart );
viewer.setKeyHandler( new GraphicalViewerKeyHandler( viewer ) );
}