public void setUseFlatUI(boolean b) {
    main.setContentAreaFilled(!b);
    main.setFocusPainted(!b);
    main.setBorderPainted(!b);
    main.setMargin(new Insets(1, 1, 1, 1));

    popper.setContentAreaFilled(!b);
    popper.setFocusPainted(!b);
    popper.setBorderPainted(!b);
    popper.setMargin(new Insets(1, 1, 1, 1));

    setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
    setOpaque(false);

    MouseAdapter ma =
        new MouseAdapter() {
          public void mouseEntered(MouseEvent e) {
            main.setContentAreaFilled(true);
            main.setBackground(new Color(216, 240, 254));
            // m.getMainButton().setForeground( Color.black );
            setBorder(new LineBorder(new Color(200, 200, 200), 1));
            setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));

            popper.setBackground(new Color(242, 242, 242));
            popper.setContentAreaFilled(true);
            popper.setBorder(menu.getBorder());
          }

          public void mouseExited(MouseEvent e) {
            main.setContentAreaFilled(false);
            //	c.setForeground( Color.black );
            setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
            setCursor(Cursor.getDefaultCursor());

            popper.setContentAreaFilled(false);
            popper.setBorder(null);
          }
        };

    main.addMouseListener(ma);
    popper.addMouseListener(ma);
  }