Adding Component above all other components

My initial problem is to put the panel (which is created as a result
of a click on a button) above all components that have been added to
the GBLTablePanel. I've written the following sample that demonstrates
my problem

package test;

import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.WindowConstants;
import javax.swing.table.DefaultTableModel;

public class GBLTablePanel extends JPanel {
    private final GridBagLayout layout;
    private final GridBagConstraints gbc;

    public GBLTablePanel() {
    layout = new GridBagLayout();
    gbc = new GridBagConstraints();
    setLayout(layout);

    JTable table = new JTable();

    table.setModel(new DefaultTableModel(new Object[][] {
        { "aaaaaaaaaaaaaaa", 3, "a", null }, { "adasda", 10, "b", null },
        { "aaaaaaaaaaaaaaa", 3, "a", null }, { "adasda", 10, "b", null },
        { "aaaaaaaaaaaaaaa", 3, "a", null }, { "adasda", 10, "b", null },
        { "aaaaaaaaaaaaaaa", 3, "a", null }, { "adasda", 10, "b", null },
        { "assssss", 55, "c", null }, { "asdafasfa", 44, "d", null } },
        new String[] { "Title 1", "Title 2", "Title 3", "Title 4" }));

    JScrollPane scrollPane = new JScrollPane(table);

    gbc.gridx = 0;
    gbc.gridy = 0;
    gbc.fill = GridBagConstraints.BOTH;
    gbc.weightx = 1.0;
    gbc.weighty = 1.0;
    layout.setConstraints(scrollPane, gbc);

    add(scrollPane);

    JButton showPanelBtn = new JButton(new AbstractAction("Show panel") {
        @Override
        public void actionPerformed(ActionEvent e) {

        /* When this button is clicked I want that panel to appear on the
top (above all components of the GBLTablePanel ) */
        JPanel panel = new JPanel();
        panel.add(new JLabel("This must be on the top of JTable"));
        panel.setSize(panel.getSize().width, 30);
        panel.setPreferredSize(new Dimension(panel.getPreferredSize().width,
30));

        layout.setConstraints(panel, gbc);
        gbc.gridy = 0;
        GBLTablePanel.this.add(panel, 0);
        }
    });

    gbc.gridwidth = GridBagConstraints.REMAINDER;
    gbc.gridy = 1;
    layout.setConstraints(scrollPane, gbc);
    add(showPanelBtn);
    }

    public static void main(String[] args) {
    JFrame f = new JFrame("Test");
    f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    /* Construct table managed by GridBagLayout */
    GBLTablePanel panel = new GBLTablePanel();
    f.add(panel);
    f.pack();
    f.setVisible(true);
    }
}

I hope the example is not too confusing, honestly I'm not sure what do
I try next to fix my problem. The panel simply does not show up :(