JDialog help

What I want to do is have a main JFrame with my application and in addition, if you press certain buttons the jframe will open up a jdialogbox that contains a jeditor pane that displays a website (eventually going to change that to open a html file from local c drive). This is going to be like a help info for user.

I need to know the best way to do this. Once the jdialog is open, when the next button is pressed to open jdialog, I want it to open it in same Jdialog and not an additional one.

The code works ok. but when i click on button one, then on button two to get the second url open. If i move around the jdialog window, then the dialog switches to the first url again. Why?????

Help Please, I'm stuck on this for a while now

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Random;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;


public class Test extends JPanel {
	
	
	public Test(){
		testing();
	}
	
	public void testing() {
	
	JPanel panel = new JPanel();
	panel.add(new JLabel("Hello"));
	JButton button = new JButton("Hello");
	JButton button2 = new JButton("Button2");

	final JDialog dialog = new JDialog();
	dialog.setVisible(false);
	dialog.setSize(800,800);
	
	button.addActionListener(new ActionListener(){
		
		public void actionPerformed(ActionEvent e) {
			
			JEditorPane pane = new JEditorPane();
			//pane.setVisible(true);
			dialog.setVisible(true);
			pane.setEditable(false);
			URL url = null;
			try {
				
				url = new URL("http://fay.iniminimo.com/paint7.html");
			} catch (MalformedURLException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			try {
				
				pane.setPage(url);
			} catch (IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}		
			dialog.add(pane);
		}
	
	});
button2.addActionListener(new ActionListener(){
		
		public void actionPerformed(ActionEvent e) {
			
			JEditorPane pane = new JEditorPane();
			//pane.setVisible(true);
			dialog.setVisible(true);
			pane.setEditable(false);
			URL url = null;
			try {
				
				url = new URL("http://www.google.ca");
			} catch (MalformedURLException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			try {
				
				pane.setPage(url);
			} catch (IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}		
			dialog.add(pane);
		}
	
	});
	
	
	panel.add(button);
	panel.add(button2);
	this.add(panel);
	
	
	
	
	}


public static void main(String[] args){
	
	JFrame frame = new JFrame();
	frame.setVisible(true);
	frame.setSize(400,400);
	Test test = new Test();
	frame.add(test);
	

}
}