ragazzi ho fatto un codice del genere per captare il mouseDown sulla mia finestra:
codice:
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * NumberAdditionUI.java
 *
 * Created on 29-gen-2009, 16.39.39
 */

package my.numeraddition;
import javax.swing.*;
import java.awt.event.MouseEvent;
/**
 *
 * @author corradocacciapuoti
 */
public class NumberAdditionUI extends javax.swing.JFrame {

    /** Creates new form NumberAdditionUI */
    public NumberAdditionUI() {
        initComponents();
    }

    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jTabbedPane1 = new javax.swing.JTabbedPane();
        jButton1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jButton1.setText("Add");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .add(141, 141, 141)
                .add(jButton1)
                .addContainerGap(151, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .add(102, 102, 102)
                .add(jButton1)
                .addContainerGap(130, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        


public void mouseDown(MouseEvent e) {
             JOptionPane.showMessageDialog(null, "Mouse Down");

}
   
    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new NumberAdditionUI().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JTabbedPane jTabbedPane1;
    // End of variables declaration                   

}
ma quando faccio il click sulla finestra non accade nulla