Tabbed Pane Focus Problems

Question

Focus traversal doesn't appear to be working on tabs added after the JFrame is initially displayed (at least on JDK 1.4.2):
1) Run the program. Focus is on the last field on the 3rd tab. Use the tab key to cycle through all components. It successfully tabs to the button, the tab, and each text field. This is working ok.
2) Create a new tab.
a) Focus should be on the last text field, but no component appears to have focus. (why???)
b) Type some character. They are added to the last text field. So focus was placed on the last text field, but the caret was not painted (why???)
c) Use the tab key to cycle through the components. When tabbing through the text fields the caret is not painted to indicate focus, except for the last text field (why???)
d) Click on a text field and use the tab key to cycle through all compnents. This time the caret will be painted for the last text field and the text field you just clicked on. (why???)
Any suggestions on how to fix this wierd behaviour? Here's my test code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TabbedPaneFocusTest
     static int columns = 0;
     public static void main(String args[])
          final JTabbedPane tabbedPane = new JTabbedPane();
          newTab(tabbedPane);
          newTab(tabbedPane);
          JComponent component = newTab(tabbedPane);
          JButton button = new JButton("Add Tab");
          button.addActionListener( new ActionListener()
               public void actionPerformed(ActionEvent e)
                    newTab(tabbedPane);
          JFrame frame = new JFrame();
          frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
          frame.getContentPane().add(tabbedPane);
          frame.getContentPane().add(button, BorderLayout.SOUTH);
          frame.setSize(400, 200);
          frame.setLocationRelativeTo( null );
          frame.setVisible(true);
          // Select tab 3 and set focus on the last text field.
          tabbedPane.setSelectedIndex(2);
          component.requestFocusInWindow();
     private static JComponent newTab(JTabbedPane tabbedPane)
          columns++;
          JComponent component = null;
          JPanel panel = new JPanel();
          for (int i = 0; i < columns; i++)
               component = new JTextField("TextField" + columns + i);
               panel.add( component );
          tabbedPane.add( panel, "" + columns );
          tabbedPane.setSelectedIndex( tabbedPane.getTabCount() - 1 );
          component.requestFocusInWindow();
          return component;
}

Answer 1

I tested the last code in Java 1.5.0 (build 1.5.0-b64) on a Linux platform, and it does not seem to work. To determine who has the focus, I added a slithy modified DefaultKeyboardManager that printed out the focus owner, when I run the modified code, it seems that the focus is placed on the last textfield when the panes are created before displaying the frame, this works ok however when I created a pane using the button, the focus is on the button and not on the text field. Apparantly pressing the button does a requestFocusInWindow() on the button after the actionPerformed is executed, overruling the requestFocusInWindow() (just my humble opinion). The modified test code follows below:
Marc
package testfocus;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Main
     static int columns = 0;
     public static void main(String args[])
          FocusManager.setCurrentKeyboardFocusManager(new DefaultKeyboardFocusManager()
                         public void processKeyEvent(Component c,KeyEvent e)
                              System.out.println("Focus owner: "+c);
                              super.processKeyEvent(c,e);
          final JTabbedPane tabbedPane = new JTabbedPane();
          newTab(tabbedPane);
          newTab(tabbedPane);
          JComponent component = newTab(tabbedPane);
          JButton button = new JButton("Add Tab");
          button.addActionListener( new ActionListener()
               public void actionPerformed(ActionEvent e)
                    newTab(tabbedPane);
          JFrame frame = new JFrame();
          frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
          frame.getContentPane().add(tabbedPane);
          frame.getContentPane().add(button, BorderLayout.SOUTH);
          frame.setSize(400, 200);
          frame.setLocationRelativeTo( null );
          frame.setVisible(true);
          // Select tab 3 and set focus on the last text field.
          tabbedPane.setSelectedIndex(2);
          component.requestFocusInWindow();
     private static JComponent newTab(JTabbedPane tabbedPane)
          columns++;
          JPanel panel = new JPanel();
          tabbedPane.add( panel, "" + columns );
          tabbedPane.setSelectedIndex( tabbedPane.getTabCount() - 1 );
          for (int i = 0; i < columns; i++)
               panel.add( new JTextField("TextField" + columns + i, 5) );
          JTextField component = (JTextField)panel.getComponent(columns - 1);
          component.requestFocusInWindow();
          return component;
}