JTabbedPane ChangeListener

通过JDK 6 Update 26（Windows 7 64位），以下示例代码仅获得一个事件：

public static void main(String[] args) {    Jframe frame = new Jframe();    frame.setDefaultCloseOperation(Jframe.DISPOSE_ON_CLOSE);    frame.setBounds(0, 0, 300, 400);    frame.setLayout(null);    final JTabbedPane tabbedPane = new JTabbedPane();    tabbedPane.addTab("One", new JPanel());    tabbedPane.addTab("Two", new JPanel());    tabbedPane.addTab("Three", new JPanel());    tabbedPane.addChangeListener(new ChangeListener() {        public void stateChanged(ChangeEvent e) { System.out.println("Tab: " + tabbedPane.getSelectedIndex());        }    });    tabbedPane.setBounds(0, 0, 300, 400);    frame.add(tabbedPane);    frame.setVisible(true);}

您能在调试器中弄清楚为什么监听器被触发了三遍吗？