Class inhertis from JButton, but button is not visible

Question

Hi!
I'm having a class that inherits JButton. The idea was to give the button additional parameters, so it inherits from JButton to have all the attributes from JButton... But the problem is, that the Buttons are only visible when I touch them with the mouse. When I move the window they are invisible again...
Does anybody know why? Thanks for your help!
P.S Sorry for my bad english....

Answer 1

Okay, thanks for that hint!
Here is the class for the gui:
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
public class Temp extends JFrame{
     private static final long serialVersionUID = 5945597724189252185L;
     private JMenuItem closeItem = null;
     private JMenuItem newItem = null;
     private JPanel mainPanel = null;
     private JLabel startImage = null;
     private MineFieldButton[][] mines = null;
     public Temp(){
          this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
          addMenu();
          this.add(getMainPanel());
          this.pack();
     private JPanel getMainPanel(){
          if (mainPanel == null){
               mainPanel = new JPanel();
               if (mines == null)
                    mainPanel.add(getStartImage());
               else{
                    mainPanel.setLayout(new GridBagLayout());
                    GridBagConstraints c = new GridBagConstraints();
                    c.fill = GridBagConstraints.HORIZONTAL;
                    c.ipady = 20;
                    c.ipadx = 20;
                    for (int x=0;x<mines.length;x++){
                         for (int y=0;y<mines[x].length;y++){
                              c.gridx = x;
                              c.gridy = y;
                              mainPanel.add(mines[x][y],c);
          return mainPanel;
     private JLabel getStartImage(){
          if(startImage == null){
               startImage = new JLabel();
          return startImage;
     private void addMenu(){
          JMenuBar menuBar = new JMenuBar();
          JMenu menu = new JMenu("File");
          menu.add(getNewItem());
          menu.add(getCloseItem());
          menuBar.add(menu);
          this.setJMenuBar(menuBar);
     private JMenuItem getNewItem(){
          if (newItem == null){
               newItem = new JMenuItem("New");
               newItem.addActionListener(new ActionListener(){
                    public void actionPerformed(ActionEvent e) {
                         createMines();
          return newItem;
     private JMenuItem getCloseItem(){
          if (closeItem == null){
               closeItem = new JMenuItem("Close");
               closeItem.addActionListener(new ActionListener(){
                    public void actionPerformed(ActionEvent e) {
                         System.exit(0);
          return closeItem;
     public void showGUI(){
          this.setVisible(true);
     private void createMines(){
          initMinesGUI();
          this.remove(getMainPanel());
          mainPanel = null;
          this.add(getMainPanel());
          this.pack();
     private void initMinesGUI(){
          mines  = new MineFieldButton[10][10];
          for (int x=0;x<mines.length;x++){
               for (int y=0;y<mines[x].length;y++){
                    mines[x][y] = new MineFieldButton();
                    mines[x][y].setBorder(BorderFactory.createRaisedBevelBorder());
                    mines[x][y].setX(x);
                    mines[x][y].setY(y);
                    mines[x][y].setNumber(x*y);
}And here for the class that inherits JButton "MineFieldButton":
import javax.swing.JButton;
public class MineFieldButton extends JButton{
     private static final long serialVersionUID = -1020769129018597011L;
     private int number = 0;
     private int x;
     private int y;
     public int getNumber() {
          return number;
     public void setNumber(int number) {
          this.number = number;
     public int getX() {
          return x;
     public void setX(int x) {
          this.x = x;
     public int getY() {
          return y;
     public void setY(int y) {
          this.y = y;
}I hope that you can find my error.... And that this is a SSCCE :-)
Thanks!