Hello I have some problems with JPanels

I Have an application, when you click a button he opens a class DatabasePaneel extends JPanel.
In that class I want to make a go back button to the previous screen (the main application) but how can I maken that???

below is the source code of the 2 classes

			package kaleidoscope;
			

			

			import java.awt.*;
			

			

			import javax.swing.*;
			

			

			import java.awt.event.*;
			

			

			/**
			

			*
			
Title: Kaleidoscope Ordersysteem
			

			*
			

			*
			
Description: Ordersysteem
			

			*
			

			*
			
Copyright: Copyright (c) 2005
			

			*
			

			*
			
Company: Projectgroep RDA
			

			*
			

			* @author Remko Hendrikse, Arnout de Jonker en Derk Dukker
			

			* @version 0.1
			

			*/
			

			public class Kaleidoscope extends JFrame {
			

			

			JPanel contentPane, pnButton;
			

			

			//private DatumPaneel datumPaneel;  //het implementeren van de datumpaneel interface
			

			DatabasePaneel pnDatabase; // het implementeren van de databasePaneel
			

			AdministratiePaneel pnAdministratie; //het implementeren van de pnAdministratie
			

			OrderPaneel pnOrder; //het implementeren van de orderPaneel
			

			PlanningPaneel pnPlanning;//het implementeren van de pnPlanning
			

			JButton btOrderInvoerPaneel, btPlanningPaneel, btAdministratiePaneel, btDatabase;
			

			

			

			private JLabel lbTitel;//, statusbar;
			

			

			FlowLayout flowLayout;
			

			GridBagLayout gridBagLayout;
			

			GridBagConstraints constraints;
			

			/**
			

			* Construct and show the application.
			

			*/
			

			public Kaleidoscope() {
			

			

			FlowLayout flowLayout = new FlowLayout();
			

			GridBagLayout gridBagLayout = new GridBagLayout();
			

			GridBagConstraints constraints = new GridBagConstraints();
			

			

			contentPane = new JPanel(flowLayout);
			

			pnButton = new JPanel(gridBagLayout);
			

			

			//datumPaneel = new DatumPaneel( "Voer datum in: " );
			

			pnDatabase = new DatabasePaneel("Voer Database gegevens in: ");
			

			pnAdministratie = new AdministratiePaneel("Administratie");
			

			pnOrder = new OrderPaneel("Orderadministratie");
			

			pnPlanning = new PlanningPaneel("Planning");
			

			

			

			btOrderInvoerPaneel = new JButton("Order invoer");
			

			btOrderInvoerPaneel.addActionListener(new OrderInvoerKnopHandler());
			

			btPlanningPaneel = new JButton("Planning");
			

			btPlanningPaneel.addActionListener(new PlanningKnopHandler());
			

			btAdministratiePaneel = new JButton("Administratie");
			

			btAdministratiePaneel.addActionListener(new AdministratieKnopHandler());
			

			btDatabase = new JButton("database");
			

			btDatabase.addActionListener(new DatabaseKnopHandler());
			

			

			

			Component strut50 = Box.createVerticalStrut(50);
			

			

			lbTitel = new JLabel("Kaleidoscope - Ordersysteem");
			

			lbTitel.setFont(new Font("Dialog", Font.BOLD, 15));
			

			//statusbar = new JLabel("status: ");
			

			

			int top = 2;            //extra ruimte aan de bovenkant
			

			int left = 2;            //extra ruimte aan de linkerkant
			

			int bottom = 2;            //extra ruimte aan de onderkant
			

			int right = 2;            //extra ruimte aan de rechterkant
			

			constraints.insets = new Insets(top, left, bottom, right); //voeg de extra ruimtes toe
			

			constraints.gridwidth = GridBagConstraints.REMAINDER;  //betekent einde van de row
			

			constraints.fill = GridBagConstraints.BOTH;     //btpen even hoog en breed
			

			

			

			

			pnButton.add(lbTitel, constraints);
			

			pnButton.add(strut50, constraints);
			

			pnButton.add(btOrderInvoerPaneel, constraints);
			

			pnButton.add(btPlanningPaneel, constraints);
			

			pnButton.add(btAdministratiePaneel, constraints);
			

			pnButton.add(btDatabase, constraints);
			

			

			contentPane.add(pnButton);         //pnButton toevoegen aan de contentPane
			

			

			setContentPane(contentPane);
			

			

			

			}
			

			

			

			class AdministratieKnopHandler implements ActionListener {
			

			

			

			public void actionPerformed(ActionEvent e) {
			

			contentPane.removeAll();
			

			contentPane.add(pnAdministratie);
			

			setContentPane(contentPane);
			

			

			}
			

			}
			

			

			class OrderInvoerKnopHandler implements ActionListener {
			

			public void actionPerformed(ActionEvent e){
			

			contentPane.removeAll();
			

			contentPane.add(pnOrder);
			

			setContentPane(contentPane);
			

			}
			

			}
			

			

			class PlanningKnopHandler implements ActionListener {
			

			public void actionPerformed(ActionEvent e){
			

			contentPane.removeAll();
			

			contentPane.add(pnPlanning);
			

			setContentPane(contentPane);
			

			

			}
			

			}
			

			

			class DatabaseKnopHandler implements ActionListener {
			

			public void actionPerformed(ActionEvent e){
			

			contentPane.removeAll();
			

			contentPane.add(pnDatabase);
			

			setContentPane(contentPane);
			

			}
			

			}
			

			

			

			public static void main(String[] args) {
			

			JFrame frame = new Kaleidoscope();
			

			frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
			

			frame.setSize( 800, 900 );
			

			frame.setTitle( "Kaleidoscope - Ordersysteem BETA 0.1" );
			

			frame.setExtendedState(Frame.MAXIMIZED_BOTH);
			

			frame.setVisible( true );
			

			

			Thread splashThread = new Thread(new SplashScreen());
			

			splashThread.start();
			

			

			

			

			}
			

			

			

			}
		

the Panel class

			package kaleidoscope;
			

			

			

			import java.awt.GridBagConstraints;
			

			import java.awt.GridBagLayout;
			

			import java.awt.Insets;
			

			import java.awt.event.*;
			

			import java.awt.*;
			

			import javax.swing.*;
			

			import javax.swing.event.*;
			

			

			/**
			

			*
			
Title: Kaleidoscope Ordersysteem
			

			*
			

			*
			
Description: Ordersysteem
			

			*
			

			*
			
Copyright: Copyright (c) 2005
			

			*
			

			*
			
Company: Projectgroep RDA
			

			*
			

			* @author Remko Hendrikse, Arnout de Jonker en Derk Dukker
			

			* @version 0.1
			

			*/
			

			public class AdministratiePaneel extends JFrame {
			

			

			Kaleidoscope kaleidoscope;
			

			DatabasePaneel pnDatabase;
			

			JButton btKlantenAdmin, btProductenAdmin, btPapiersoortAdmin, btTerug,
			

			btPalletsoortAdmin, btSnijmaatAdmin, btDiameterAdmin, btDoosFormaatAdmin, btDatabaseAdmin ;
			

			JLabel lbAdministratie, test;
			

			JPanel pnButton, pnBasis;
			

			//Container container;
			

			

			FlowLayout flowLayout;
			

			

			GridBagLayout gridBagLayout;
			

			GridBagConstraints constraints;
			

			

			public AdministratiePaneel(String omschrijving) {
			

			

			

			//Container container = getContentPane();
			

			flowLayout = new FlowLayout();
			

			pnBasis = new JPanel(flowLayout);
			

			

			pnDatabase = new DatabasePaneel("Database gegevens");
			

			//this.setLayout(flowLayout);
			

			GridBagLayout gridBagLayout = new GridBagLayout();
			

			GridBagConstraints constraints = new GridBagConstraints();
			

			

			pnButton = new JPanel(gridBagLayout);
			

			

			int top = 2;            //extra ruimte aan de bovenkant
			

			int left = 2;            //extra ruimte aan de linkerkant
			

			int bottom = 2;            //extra ruimte aan de onderkant
			

			int right = 2;            //extra ruimte aan de rechterkant
			

			constraints.insets = new Insets(top, left, bottom, right); //voeg de extra ruimtes toe
			

			constraints.gridwidth = GridBagConstraints.REMAINDER;  //betekent einde van de row
			

			constraints.fill = GridBagConstraints.BOTH;     //knoppen even hoog en breed
			

			

			

			btKlantenAdmin      = new JButton("Klanten administratie");
			

			btProductenAdmin  = new JButton("Productenadministratie");
			

			btPapiersoortAdmin  = new JButton("Papiersoorten administratie");
			

			btPalletsoortAdmin  = new JButton("Palletsoorten administratie");
			

			btSnijmaatAdmin     = new JButton("Snijmaat administratie");
			

			btDiameterAdmin     = new JButton("Diameters administratie");
			

			btDoosFormaatAdmin  = new JButton("Doosformaat administratie");
			

			btDatabaseAdmin  = new JButton("Database verbindinggegevens");
			

			btDatabaseAdmin.addActionListener(new DatabaseKnopHandler());
			

			btTerug    = new JButton("Terug naar hoofdmenu");
			

			btTerug.addActionListener(new TerugKnopHandler());
			

			

			constraints.insets = new Insets(top, left, bottom, right); //voeg de extra ruimtes toe
			

			constraints.gridwidth = GridBagConstraints.REMAINDER;  //betekent einde van de row
			

			constraints.fill = GridBagConstraints.BOTH;     //knoppen even hoog en breed
			

			

			lbAdministratie = new JLabel("Adminstratie");
			

			lbAdministratie.setFont(new Font("Dialog", Font.BOLD, 15));
			

			lbAdministratie.setVerticalTextPosition(JLabel.CENTER);
			

			lbAdministratie.setHorizontalTextPosition(JLabel.CENTER);
			

			

			test = new JLabel();
			

			

			

			Component strut50 = Box.createVerticalStrut(50);
			

			

			pnButton.add(lbAdministratie, constraints);
			

			pnButton.add(strut50, constraints);
			

			

			pnButton.add(btDoosFormaatAdmin, constraints);
			

			

			pnButton.add(btKlantenAdmin, constraints);
			

			

			pnButton.add(btProductenAdmin, constraints);
			

			

			pnButton.add(btPapiersoortAdmin, constraints);
			

			

			pnButton.add(btPalletsoortAdmin, constraints);
			

			

			pnButton.add(btSnijmaatAdmin, constraints);
			

			

			pnButton.add(btDiameterAdmin, constraints);
			

			

			pnButton.add(btDatabaseAdmin, constraints);
			

			pnButton.add(test, constraints);
			

			

			pnBasis.add(pnButton);
			

			

			add(pnDatabase).setVisible(false);
			

			

			add(pnBasis);
			

			

			add(btTerug, constraints);
			

			

			

			

			

			}
			

			

			class DatabaseKnopHandler implements ActionListener {
			

			

			public void actionPerformed(ActionEvent e){
			

			

			pnBasis.removeAll();
			

			pnDatabase.setVisible(true);
			

			

			}
			

			}
			

			

			class TerugKnopHandler implements ActionListener {
			

			

			public void actionPerformed(ActionEvent e){
			

			//return to the main screen kaleidoscope.java
			

			

			}
			

			}
			

			}