JPanel main = builder.getPanel();
main.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
ButtonBarBuilder bb = new ButtonBarBuilder();
bb.addGlue();
bb.addGridded(ok);
bb.addGridded(cancel);
bb.addGlue();
getContentPane().add(main, BorderLayout.CENTER);
getContentPane().add(bb.getPanel(), BorderLayout.SOUTH);