private JTable table = new JTable(20, 6) {
        public JToolTip createToolTip() {
            JToolTip tip = super.createToolTip();
            tip.setLayout(new BorderLayout());
            tip.add(new JButton("Hello"), BorderLayout.NORTH);
            tip.add(new JButton("Hello"), BorderLayout.SOUTH);
            tip.setPreferredSize(new Dimension(300, 200));
            return tip;
        }
    };