Mystery: GridBagLayout on Panel1 lost after adding Panel1 on Panel1

Question

This is puzzling me.
The buttons b1 and b2 should appear at the bottom because "c.anchor=GridBagConstraints.PAGE_END;"
Instead it appears at the centre. The problem only appears when Panel containing the GridBagLayout is added to another Panel.
If anyone knows the answer to this?...............Is it a bug?
using java SDK1.4.
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
public class TestPanel extends JPanel {
public TestPanel() {
super();
setBorder(BorderFactory.createTitledBorder("p"));
GridBagLayout glayout = new GridBagLayout();
GridBagConstraints constraints = new GridBagConstraints();
JPanel p1 = new JPanel();
Dimension size = new Dimension(100,300);
p1.setPreferredSize(size);
p1.setBorder(BorderFactory.createTitledBorder("p1"));
p1.setLayout(glayout);
JButton b1 = new JButton("b1");
JButton b2 = new JButton("b2");
addComponent(p1, glayout, constraints, b1, 0, 0, 1, 1);
addComponent(p1, glayout, constraints, b2, 1, 0, 1, 1);
add(p1);
private static void createAndShowGUI() {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("buttons suppose to be at bottom of Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
TestPanel newContentPane = new TestPanel();
newContentPane.setOpaque(true);
frame.setContentPane(newContentPane);
frame.pack();
frame.setVisible(true);
private void addComponent(JPanel p, GridBagLayout g, GridBagConstraints c,
Component component, int row, int column, int width, int height )
c.gridx= column;
c.gridy=row;
c.gridwidth=width;
c.gridheight=height;
c.fill=GridBagConstraints.NONE;
c.anchor=GridBagConstraints.PAGE_END; ///Why anchoring not working?
g.setConstraints(component, c);
p.add( component );
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}

Answer 1

Found the problem. forgot the weights. Thanks.
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
public class TestPanel extends JPanel {
public TestPanel() {
super(new GridLayout(0,1));
setBorder(BorderFactory.createTitledBorder("p"));
GridBagLayout glayout = new GridBagLayout();
GridBagConstraints constraints = new GridBagConstraints();
JPanel p1 = new JPanel();
Dimension size = new Dimension(100,300);
p1.setPreferredSize(size);
p1.setBorder(BorderFactory.createTitledBorder("p1"));
p1.setLayout(glayout);
JButton b1 = new JButton("b1");
JButton b2 = new JButton("b2");
setLayout(new GridBagLayout());
addComponent(p1, glayout, constraints, b1, 0, 0, 1, 1, 0, 0);
addComponent(p1, glayout, constraints, b2, 1, 0, 1, 1, 1, 1);//adding weights
add(p1 );
private static void createAndShowGUI() {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("buttons suppose to be at bottom of Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
TestPanel newContentPane = new TestPanel();
newContentPane.setOpaque(true);
frame.setContentPane(newContentPane);
frame.pack();
frame.setVisible(true);
private void addComponent(JPanel p, GridBagLayout g, GridBagConstraints c,
Component component, int row, int column, int width, int height,
int weighty, int weightx)
c.gridx= column;
c.gridy=row;
c.gridwidth=width;
c.gridheight=height;
c.anchor=GridBagConstraints.NORTHWEST;
c.weighty = weighty; //added................
c.weightx= weightx; //added....
p.add(component, c);
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}