GridBagLayout and Panel Border problem

Question

I have 3 panels like
A
B
C
and the C panel has a Mouse Listener that on a mouseEntered creates a border around the same panel and on a mouseExited clears that border.
When this border is created the A and B panels go up a little bit .. they move alone when the border is created.
Is there any way to fix this problem? Is there any way to get the panels static?
the code is close to the following:
import java.awt.*;
import javax.swing.*;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
import javax.swing.BorderFactory;
import javax.swing.border.Border;
import javax.swing.border.TitledBorder;
import java.awt.event.*;
import java.text.NumberFormat;
public class Game extends JFrame implements MouseListener
JPanel game, options, top, down, middle;
NumberFormat nf;
public Game() {
super("Game");
nf = NumberFormat.getPercentInstance();
nf.setMaximumFractionDigits(1);
JPanel center = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.fill = gbc.BOTH;
gbc.weighty = 1.0;
gbc.weightx = 0.8;
center.add(getGamePanel(), gbc);
gbc.weightx = 0.104;
center.add(getOptionsPanel(), gbc);
Container cp = getContentPane();
// use the JFrame default BorderLayout
cp.add(center); // default center section
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setSize(700,600);
// this.setResizable(false);
setLocationRelativeTo(null);
setVisible(true);
addComponentListener(new ComponentAdapter()
public void componentResized(ComponentEvent e)
showSizeInfo();
showSizeInfo();
private void showSizeInfo()
Dimension d = getContentPane().getSize();
double totalWidth = game.getWidth() + options.getWidth();
double gamePercent = game.getWidth() / totalWidth;
double optionsPercent = options.getWidth() / totalWidth;
double totalHeight = top.getHeight() + middle.getHeight() + down.getHeight();
double topPercent = top.getHeight() / totalHeight;
double middlePercent = middle.getHeight() / totalHeight;
double downPercent = down.getHeight() / totalHeight;
System.out.println("content size = " + d.width + ", " + d.height + "\n" +
"game width = " + nf.format(gamePercent) + "\n" +
"options width = " + nf.format(optionsPercent) + "\n" +
"top height = " + nf.format(topPercent) + "\n" +
"middle height = " + nf.format(middlePercent) + "\n" +
"down height = " + nf.format(downPercent) + "\n");
private JPanel getGamePanel()
// init components
top = new JPanel(new BorderLayout());
top.setBackground(Color.red);
top.add(new JLabel("top panel", JLabel.CENTER));
middle = new JPanel(new BorderLayout());
middle.setBackground(Color.green.darker());
middle.add(new JLabel("middle panel", JLabel.CENTER));
down = new JPanel(new BorderLayout());
down.setBackground(Color.blue);
down.add(new JLabel("down panel", JLabel.CENTER));
// layout game panel
game = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.weightx = 1.0;
gbc.fill = gbc.BOTH;
gbc.gridwidth = gbc.REMAINDER;
gbc.weighty = 0.2;
game.add(top, gbc);
gbc.weighty = 0.425;
game.add(middle, gbc);
gbc.weighty = 0.2;
game.add(down, gbc);
down.addMouseListener(this);
return game;
private JPanel getOptionsPanel()
options = new JPanel(new BorderLayout());
options.setBackground(Color.pink);
options.add(new JLabel("options panel", JLabel.CENTER));
return options;
// mouse listener events
     public void mouseClicked( MouseEvent e ) {
System.out.println("pressed");
     public void mousePressed( MouseEvent e ) {
     public void mouseReleased( MouseEvent e ) {
     public void mouseEntered( MouseEvent e ) {
Border redline = BorderFactory.createLineBorder(Color.red);
JPanel x = (JPanel) e.getSource();
x.setBorder(redline);
     public void mouseExited( MouseEvent e ){
JPanel x = (JPanel) e.getSource();
x.setBorder(null);
public static void main(String[] args ) {
Game exe = new Game();
exe.show();
}

Answer 1

import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
import java.text.NumberFormat;
public class Game extends JFrame implements MouseListener{
  JPanel game, options, top, down, middle;
  NumberFormat nf;
  public Game() {
    super("Game");
    nf = NumberFormat.getPercentInstance();
    nf.setMaximumFractionDigits(1);
    JPanel center = new JPanel(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.fill = gbc.BOTH;
    gbc.weighty = 1.0;
    gbc.weightx = 0.8;
    center.add(getGamePanel(), gbc);
    gbc.weightx = 0.104;
    center.add(getOptionsPanel(), gbc);
    Container cp = getContentPane();
    // use the JFrame default BorderLayout
    cp.add(center); // default center section
    this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    this.setSize(700,600);
    // this.setResizable(false);
    setLocationRelativeTo(null);
    setVisible(true);
    addComponentListener(new ComponentAdapter(){
        public void componentResized(ComponentEvent e){
        showSizeInfo();
    showSizeInfo();
  private void showSizeInfo(){
    Dimension d = getContentPane().getSize();
    double totalWidth = game.getWidth() + options.getWidth();
    double gamePercent = game.getWidth() / totalWidth;
    double optionsPercent = options.getWidth() / totalWidth;
    double totalHeight = top.getHeight() + middle.getHeight() + down.getHeight();
    double topPercent = top.getHeight() / totalHeight;
    double middlePercent = middle.getHeight() / totalHeight;
    double downPercent = down.getHeight() / totalHeight;
    System.out.println("content size = " + d.width + ", " + d.height + "\n" +
        "game width = " + nf.format(gamePercent) + "\n" +
        "options width = " + nf.format(optionsPercent) + "\n" +
        "top height = " + nf.format(topPercent) + "\n" +
        "middle height = " + nf.format(middlePercent) + "\n" +
        "down height = " + nf.format(downPercent) + "\n");
  private JPanel getGamePanel(){
    // init components
    top = new JPanel(new BorderLayout());
    top.setBackground(Color.red);
    top.add(new JLabel("top panel", JLabel.CENTER));
    middle = new JPanel(new BorderLayout());
    middle.setBackground(Color.green.darker());
    middle.add(new JLabel("middle panel", JLabel.CENTER));
    down = new JPanel(new BorderLayout());
    down.setBackground(Color.blue);
    down.add(new JLabel("down panel", JLabel.CENTER));
    // layout game panel
    game = new JPanel(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.weightx = 1.0;
    gbc.fill = gbc.BOTH;
    gbc.gridwidth = gbc.REMAINDER;
    gbc.weighty = 0.2;
    game.add(top, gbc);
    gbc.weighty = 0.425;
    game.add(middle, gbc);
    gbc.weighty = 0.2;
    game.add(down, gbc);
    down.addMouseListener(this);
    return game;
  private JPanel getOptionsPanel(){
    options = new JPanel(new BorderLayout());
    options.setBackground(Color.pink);
    options.add(new JLabel("options panel", JLabel.CENTER));
    return options;
  public void mouseClicked( MouseEvent e ) {
    System.out.println("pressed");
  public void mousePressed( MouseEvent e ) {
  public void mouseReleased( MouseEvent e ) {
  public void mouseEntered( MouseEvent e ) {
    Border redline = new CalmLineBorder(Color.red);
    JPanel x = (JPanel) e.getSource();
    x.setBorder(redline);
  public void mouseExited( MouseEvent e ){
    JPanel x = (JPanel) e.getSource();
    x.setBorder(null);
  public static void main(String[] args ) {
    Game exe = new Game();
    exe.setVisible(true);
class CalmLineBorder extends LineBorder{
  public CalmLineBorder(Color c){
    super(c);
  public CalmLineBorder(Color c, int thick){
    super(c, thick);
  public CalmLineBorder(Color c, int thick, boolean round){
    super(c, thick, round);
  public Insets getBorderInsets(Component comp){
    return new Insets(0, 0, 0, 0);
}