I need two combo boxes in a singel frame

Hi guys am trying to add two comboboxes in a frame. but am getting the problem in that. Kindly help me. i have tried many things but couldn't rectify the problem.

Code:

---

public class IndexPerformanceView extends JFrame implements ActionListener {
    private static final long serialVersionUID = 1L;
    private IndexPerformanceControl model;
    private Box filter;
    private JComboBox xchg;
    private JComboBox chgtype;
    private JFrame jframe;
    private Object ContentPane;
    public static int selectedindex;
public IndexPerformanceView() {

              this.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
        this.setIconImage(Images.LoadImage("icon.gif"));
        model = new IndexPerformanceControl();
        this.getContentPane().add(model, BorderLayout.SOUTH);
        xchg = new JComboBox(new String[] { "NSE" });
        xchg.addActionListener(this);
        this.getContentPane().add(xchg, BorderLayout.CENTER);
        chgtype = new JComboBox(new String[] { "Change%", "Change" });
        chgtype.addActionListener(this);
        labelpanel.add(chgtype);
        this.getContentPane().add(chgtype, BorderLayout.EAST);
        this.pack();
        this.setTitle("IDX Performance");
        this.setBounds(100, 100, 600, 480);
    }

---

I am trying to add two comboboxes xchg and chgtype at the top of the frame. but when i do it am getting the problem. I will send you the screenshot..

Why are you adding chgtype to both labelpanel and to the root pane and what is labelpanel, it isn't declared anywhere.