GridBagLayout in CardLayout....Problems

Hello,
i have a probleme with the cardLayout.

i have a jpanel with cardlayout and two cards in it with GridBagLayout.
In each card is a JButton. At a click there should be shown the next card with the other button.
But the buttons will be shown together when i start the program.

My Code:
[code]
package EP.GUI;
import static EP.UTIL.Sprache_DE.stRegeln;
import static java.awt.GridBagConstraints.BOTH;
import static java.awt.GridBagConstraints.LINE_START;
import static java.awt.GridBagConstraints.REMAINDER;

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class CardLayoutExample1 extends MyGridBagContraints{
  
    private CardLayout cardLayout;
    public JButton button1, button2;
    private JPanel panel1, panel2, jPanelEigen, jPanelGridBag;
    

  
  public CardLayoutExample1(){
      super();
      
      this.setSize(500,500);
        this.setLayout(new GridBagLayout());
        this.setVisible(true);
        this.setLocation(50,50);
        this.setTitle(stRegeln);
        this.addWindowListener(new WindowListener() {
            public void windowOpened(WindowEvent arg0) {}
            public void windowIconified(WindowEvent arg0) {}
            public void windowDeiconified(WindowEvent arg0) {}
            public void windowDeactivated(WindowEvent arg0) {}
            public void windowClosing(WindowEvent arg0) {

            }
            public void windowClosed(WindowEvent arg0) {}
            public void windowActivated(WindowEvent arg0) {}
        });

    cardLayout = new CardLayout();
    jPanelEigen = new JPanel(cardLayout);
    
    panel1 = new JPanel(new GridBagLayout());
    panel2 = new JPanel(new GridBagLayout());
  
    button1 = new JButton("Button1");
    button2 = new JButton("Button2");
    
    jPanelEigen.add(getPanel1(), "card1");
    jPanelEigen.add(getPanel2(), "card2");
    
    cardLayout.show(jPanelEigen, "card1");
    this.add(jPanelEigen);
    pack();
    createListener();
    setVisible(true);
  }

  private JPanel getPanel1(){
      
      panel1.setBackground(Color.gray);
      setDefaultGB();
        addGB(button1, gridx, gridy,
                gridwidth = REMAINDER, gridheight, fill,
                weightx, weighty, anchor,
                insets);
        
        return panel1;
  }
  private JPanel getPanel2(){
      
      panel2.setBackground(Color.yellow);
      setDefaultGB();
        addGB(button2, gridx, gridy,
                gridwidth = REMAINDER, gridheight, fill,
                weightx, weighty, anchor,
                insets);
      
      return panel2;
  }
  
  
  private void createListener(){
    ActionListener al = new ActionListener(){
      public void actionPerformed(ActionEvent e){
        cardLayout.next(jPanelEigen);
      }
    };
    button1.addActionListener(al);
    button2.addActionListener(al);
    
    addWindowListener(new WindowAdapter(){
      public void windowClosing(WindowEvent e){
        System.exit(0);
      }
    });
  }
}

[/code]

I have no idea what to do and hope you can help me.
Thanks.