public DetectCalibrationChessApp() { gray = new ImageFloat32(1, 1); JPanel panel = new JPanel(); panel.setLayout(new BorderLayout()); calibGUI = new GridCalibPanel(true); calibGUI.setListener(this); calibGUI.setMinimumSize(calibGUI.getPreferredSize()); panel.add(gui, BorderLayout.CENTER); panel.add(calibGUI, BorderLayout.WEST); gui.addMouseListener( new MouseAdapter() { @Override public void mousePressed(MouseEvent e) { System.out.println("clicked at " + e.getX() + " " + e.getY()); } }); setMainGUI(panel); }