BUG REPORT: 2 JTextComponents using the same Document

Question

When 2 JTextComponents use the same Document they should show the same.
However when you add them to JTabbedPane to 2 different tabs, one does not show the document correctly, until you resize the window.
Compile and run the code example to see for yourself.
If you append "<first message"> and "<second message>" the first tab will show the correct document:
<first message>
<second message>
But if you then switch to the second tab (do not switch to it earlier), you will see:
<first message><second message>
<second message>
Add some more messages to see the effect and then resize the window to see the problem dissappear magically.
--> Code example <--
package testproject;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
* @author Geoffrey
public class TestProject extends JFrame implements ActionListener {
     public static void main(String[] args) {
          TestProject currentFrame = new TestProject();
          currentFrame.pack();
          currentFrame.setExtendedState(JFrame.MAXIMIZED_BOTH); // Optional
          currentFrame.setVisible(true);
     private JLabel label = new JLabel("Append 2 or more different messages and switch tab. "
     + "Resizing the window will solve the bug.");
     private JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP,
                                                                                     JTabbedPane.WRAP_TAB_LAYOUT);
     private JTextField textField = new JTextField("<first message>");
     private JButton button = new JButton("Append message");
     private StyledDocument document = new DefaultStyledDocument();
     private JTextPane firstTextPane;
     private JTextPane secondTextPane;
     public TestProject() {
          super("TestProject");
          setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
          // configure the components
          firstTextPane = new JTextPane(document); // Uses the same document as secondTextPane
          tabbedPane.add("Orginal tab", firstTextPane);
          secondTextPane = new JTextPane(document); // Uses the same document as firstTextPane
          tabbedPane.add("Click here after appending 2 different messages", secondTextPane);
          textField.addActionListener(this);
          button.addActionListener(this);
          // configure the layout and add the components
          Container contentPanel = getContentPane();
          GridBagLayout layout = new GridBagLayout();
          contentPanel.setLayout(layout);
GridBagConstraints constraints = new GridBagConstraints();
          constraints.fill = GridBagConstraints.BOTH;
          constraints.insets = new Insets (10, 10, 10, 10);
          constraints.weightx = 1.0;
          constraints.weighty = 0.0;
          constraints.gridx = 0;
          constraints.gridy = 0;
          contentPanel.add(label, constraints);
          constraints.weighty = 1.0;
          constraints.gridy = 1;
          contentPanel.add(tabbedPane, constraints);
          constraints.weighty = 0.0;
          constraints.gridy = 2;
          contentPanel.add(textField, constraints);
          constraints.gridy = 3;
          contentPanel.add(button, constraints);
     public void actionPerformed(ActionEvent event) {
          String message = textField.getText();
          SimpleAttributeSet simpleAttributeSet = new SimpleAttributeSet();
          StyleConstants.setFontFamily(simpleAttributeSet, "Monospaced");
          StyleConstants.setForeground(simpleAttributeSet, Color.BLACK);
          try {
               document.insertString(document.getLength(), message + "\n",
                                                  simpleAttributeSet);
          } catch (BadLocationException exception) {}

Answer 1

duplicate of:
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closing and locking
Ludek