(Auto-)Growing Panes

In another Swing-related weirdness note, it seems that a certain combination of apparently logical options regarding GridBagConstraints and a JTextArea will cause the JTextArea and enclosing JPanel to expand horizontally by gridBagContraints.ipadx pixels per step, forever.

After scratching my chin in confusion, I whittled out the following minimalish example that demonstrates the result:

import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;

import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.border.LineBorder;

public class TextAreaExample {
 public JPanel createContentPane() {

  JPanel contentPane = new JPanel();

  JPanel mainPanel = new JPanel(new GridBagLayout());
  GridBagConstraints c = new GridBagConstraints();
  // ipadx > 0 causes textarea panel to grow horizontally forever if linewrap is set!
  c.ipadx = 1;

  JPanel leftPanel = new JPanel();
  leftPanel.add(new JLabel("Left"));
  mainPanel.add(leftPanel, c);

  JPanel logPanel = new JPanel();
  logPanel.setLayout(new BoxLayout(logPanel, BoxLayout.PAGE_AXIS));

  JLabel label = new JLabel("Hello");
  logPanel.add(label);

  // create misbehaving textarea
  JTextArea log = new JTextArea(10, 40);
  log.setLineWrap(true);
  log.setBorder(new LineBorder(Color.BLUE));
  logPanel.add(log);

  mainPanel.add(logPanel, c);

  JPanel rightPanel = new JPanel();
  rightPanel.add(new JLabel("Right"));
  mainPanel.add(rightPanel, c);

  contentPane.add(mainPanel);
  return contentPane;
 }

 private static void createAndShowGUI() {
  JFrame frame = new JFrame("JTextArea growth test");

  TextAreaExample demo = new TextAreaExample();
  frame.setContentPane(demo.createContentPane());

  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.pack();
  frame.setVisible(true);
 }

 public static void main(String[] args) {
  SwingUtilities.invokeLater(new Runnable() {
   public void run() {
    createAndShowGUI();
   }
  });
 }
}

I can get around it by setting a preferred size on the JTextArea (a size of 0,0 seems to do the trick without changing the initial layout), but what the hell?