FULL PRODUCT VERSION :
java 1.6.

ADDITIONAL OS VERSION INFORMATION :
Windows Vista

A DESCRIPTION OF THE PROBLEM :
If in a Yes/No dialog where Yes is default you shift focus to No by using the Tab key and then use the Return key you still get the Yes result.


REPRODUCIBILITY :
This bug can be reproduced always.

To reproduce:
1. Run the application
2. Press "tab" key to switch selection to "No"
3. Press "enter" shows the selection is Yes.

---------- BEGIN SOURCE ----------
import javax.swing.JOptionPane;
/*
 * demo.java
 *
 * Created on den 22 augusti 2007, 08:45
 */

/**
 *
 * @author bosy
 */
public class demo extends javax.swing.JFrame {
   
    /** Creates new form demo */
    public demo() {
        initComponents();
       
        if(JOptionPane.YES_OPTION==JOptionPane.showConfirmDialog(this,
                "Do you really want to close this unsaved file ?",
                "Confirm",
                JOptionPane.YES_NO_OPTION)){
            jTextField1.setText("Option YES was selected");
        } else {
            jTextField1.setText("Option NO was selected");
        }
    }
   
    /** 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.
     */
    // <editor-fold defaultstate="collapsed" desc=" Generated Code
">
    private void initComponents() {
        jTextField1 = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        jTextField1.setEditable(false);
        jTextField1.setFont(new java.awt.Font("Tahoma", 1, 12));
        jTextField1.setForeground(new java.awt.Color(255, 51, 102));
        jTextField1.setHorizontalAlignment(javax.swing.JTextField.CENTER);

        javax.swing.GroupLayout layout = new
javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(74, 74, 74)
                .addComponent(jTextField1,
javax.swing.GroupLayout.PREFERRED_SIZE, 248,
javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(78, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(90, 90, 90)
                .addComponent(jTextField1,
javax.swing.GroupLayout.PREFERRED_SIZE, 31,
javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(120, Short.MAX_VALUE))
        );
        pack();
    }// </editor-fold>
   
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new demo().setVisible(true);
            }
        });
    }
   
    // Variables declaration - do not modify
    private javax.swing.JTextField jTextField1;
    // End of variables declaration
   
}
---------- END SOURCE ----------


CUSTOMER SUBMITTED WORKAROUND :
Press Space or click with the mouse you get the desired No result.