private void changeLookAndFeel(LookAndFeel laf) {
        try {
            UIManager.setLookAndFeel(laf);
            SwingUtilities.updateComponentTreeUI(this);
            this.pack();
        } catch (UnsupportedLookAndFeelException ex) {
            Logger.getLogger(FrameMain.class.getName()).log(Level.SEVERE, null, ex);
        }
    }