Page not refreshing properly within a swing JApplet

[Majora94]

Hi, I started java about a week ago and have been trying to make a swing JApplet for a college assignment. The problem I am getting is that when you click a button on the main page, you can see the compnents of the next page rearanging slightly before they are displayed. Is this a problem with my code or does this have to happen?

My JApplet ishere. You will see what I am talking about when you navigate to a page by clicking a button on the menu.

Here is my code for any suggestions. (BTW am I even initialising properly? I'm still new and not quite sure so any help will be much appretiated)

import java.awt.*;
import java.applet.*;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;

public class main extends JApplet
{
	JPanel screen = new JPanel();
	
	int width;
	
	int menuOption = 0;
	int numberOfOptions = 9;
	String[] optionNames = {
		"Local Variables", 
			"Procedures", 
				"Functions", 
					"Loops (for)", 
						"Loops (while)", 
							"Conditional Statements", 
								"Boolean Operators", 
									"Perameter Passing", 
										"Debugging"
											};
	
	public void init()
	{
		
		try
		{
			SwingUtilities.invokeAndWait(new Runnable() {
            	public void run() {
					start();
            	}
        	});
		}
		catch(Exception e)
		{
			
			System.out.println("Failure to init: "+e);
		}
	}										
											
	public main()
	{
		programSwitch();
	}
	
	public void programSwitch()
	{
		screen.removeAll();
		switch(menuOption)
		{
			case 0:
				menu();
				break;
			case 1:
				VariablesPage();
				break;
			case 2:
				VariablesPage();
				break;
			case 3:
				VariablesPage();
				break;
			case 4:
				VariablesPage();
				break;
			case 5:
				VariablesPage();
				break;
			case 6:
				VariablesPage();
				break;
			case 7:
				VariablesPage();
				break;
			case 8:
				VariablesPage();
				break;
			case 9:
				VariablesPage();
				break;
			default:
				menu();
				break;
		}
		revalidate();
	}
	
	public void menu()
	{
		screen.setLayout(new BorderLayout());
		add(screen);
		
		JPanel titlePanel = new JPanel();
		screen.add(titlePanel, BorderLayout.NORTH);
		
		JLabel title = new JLabel("Basic Programming Tutorials");
		titlePanel.add(title);
		
		JPanel menuPanel = new JPanel();
		menuPanel.setLayout(new GridLayout(0,3));
		screen.add(menuPanel, BorderLayout.CENTER);
		
		
		JButton[] menuOptions = new JButton[numberOfOptions];
		for(int i = 0; i < numberOfOptions; i++)
		{
			menuOptions[i] = new JButton(optionNames[i]);
			menuPanel.add(menuOptions[i]);
			
			menuOptions[i].addActionListener(new ActionListener()
			{
				public void actionPerformed(ActionEvent e)
				{
					handleMenuSelect(e.getActionCommand());
				}
			});
		}
		
	}
	
	public void handleMenuSelect(String option)
	{
		for( int i = 0; i < numberOfOptions; i++)
		{
			if( option == optionNames[i])
			{
				menuOption = i+1;
				programSwitch();				
			}
		}
	}
	
	public void VariablesPage()
	{		
		width = getSize().width;
		screen.setLayout(new BorderLayout());
		add(screen);
		
		JPanel titlePanel = new JPanel();
		screen.add(titlePanel, BorderLayout.NORTH);		
		
		JLabel title = new JLabel(optionNames[menuOption-1]);
		titlePanel.add(title);
		
		JPanel contentPanel = new JPanel();
		contentPanel.setLayout(new BorderLayout());
		screen.add(contentPanel, BorderLayout.CENTER);
		
		JPanel content = new JPanel();
		content.setLayout(new GridBagLayout());
		GridBagConstraints c = new GridBagConstraints();
		contentPanel.add(content, BorderLayout.NORTH);		
		
		JTextArea thankNote = new JTextArea();
		thankNote.setText("This text area will contain information and tutorials about "+optionNames[menuOption-1]);
		thankNote.setEditable(false);
		thankNote.setLineWrap(true);
		c.weightx = 1.0;
		//c.anchor = GridBagConstraints.NORTHWEST;
		c.gridx = 1;
		c.gridwidth = 2;
		c.fill = GridBagConstraints.BOTH;
		c.insets = new Insets(10,10,10,10);
		content.add(thankNote, c);
		
		JPanel pageControlPanel = new JPanel();
		pageControlPanel.setBackground(Color.black);
		c.weightx = 1.0;
		c.gridx = 3;
		c.gridwidth = 1;
		c.ipadx = (width/3)-20;
		c.fill = GridBagConstraints.BOTH;
		c.insets = new Insets(10,10,10,10);
		content.add(pageControlPanel, c);
		
		JButton homeButton = new JButton("HOME");
		screen.add(homeButton, BorderLayout.SOUTH);
		
		homeButton.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				menuOption = 0;
				programSwitch();
			}
		});
	}
}

[Norm]

Where have you read about writing java applets?
Normally applets do not use their constructors.
Where is the start() method defined that you are calling in the run() method?