I am having problems understanding why two JPanels do not display correctly in the JTabbedPane container I have created. (the other two do display correctly, with different LayoutManagers for each]

WebBrowser is has line with URL browswer line
and then a JEditorPane. [I copied the code for this pane straight from our assignment in my classroom, but in class we just used a JFrame for a container, not a JTabbedPane extending a JFrame, and JPanels inside the JTabbedPane] Can you put a JEditorPane inside a JPane, inside a JTabbedPane?

TaxReport just has simle JLabels and three separate JPanels in a BorderLayout

Why do these not display correctly?

STARTUP MAIN CLASS
Code:
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import java.util.*;

public class StartUp extends JFrame implements ActionListener
{
    JFrame frame = new JFrame("Tool Inventory");
    JTabbedPane jtp = new JTabbedPane();
    
    InputPanel tab1 = new InputPanel();
    SearchPanel tab2 = new SearchPanel();
    ShowPanel tab3 = new ShowPanel();
    WebBrowser tab4 = new WebBrowser();
    TaxReport tab5 = new TaxReport();
    
    /** Creates a new instance of StartUp */
    public StartUp() 
    {
        frame.setSize(650,500);
        frame.setLocation(75,30);
        frame.getContentPane().add(jtp);
        jtp.add("Input Tool", tab1);
        jtp.add("Search File",tab2);
        jtp.add("Show File Contents",tab3);
        jtp.add("Search Web",tab4);
        jtp.add("Tax Report",tab5);
        
        frame.addWindowListener(new WindowAdapter()
        {
          public void windowClosing(WindowEvent e)
          {
             System.exit(0);   
          }
        });
        
        frame.setVisible(true);
    }
    
    public static void main(String[] args)
    {
       new StartUp();
       
    }
    
    public void actionPerformed(ActionEvent e) 
    {
    
    }
    
}
WEBBROWSER CLASS
Code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.net.*;
import java.io.*;


public class WebBrowser extends JPanel implements ActionListener,HyperlinkListener


{
    URL url;
    JLabel urlLine = new JLabel("URL");
    JTextField text = new JTextField(30);
    JEditorPane edit= new JEditorPane();
    
    
    public WebBrowser() 
    {
        this.setSize(400,400);
        this.setLocation(10, 10);
        edit.setEditable(false);
        text.addActionListener(this);
        edit.addHyperlinkListener(this);
        this.add(urlLine,BorderLayout.NORTH);
        this.add(text,BorderLayout.NORTH);
        this.add(edit,BorderLayout.CENTER);
        
        try
        {
         url = new URL("http://search.yahoo.com");   
         edit.setPage(url);
        }
        
        catch (Exception e)
        {
            
        }
    }
    
    public void actionPerformed(ActionEvent e) 
    {
        try{
       URL browserLine = new URL(text.getText());
       edit.setPage(browserLine);
        }
        
        catch (Exception error)
        {
            
        }
    }
    
    public void hyperlinkUpdate(HyperlinkEvent e) 
    {
        HyperlinkEvent.EventType type = e.getEventType();
        
        try
        {
            if (type==HyperlinkEvent.EventType.ACTIVATED)
                edit.setPage(e.getURL()); 
                           
            else if (type==HyperlinkEvent.EventType.ENTERED)
                text.setText(e.getURL()+"");
            
            else if (type==HyperlinkEvent.EventType.EXITED)
                text.setText("");
        }
        
        catch (Exception ex)
        {
            
        }
    }
    
}
TAXREPORT CLASS
Code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class TaxReport extends JPanel implements ActionListener
{
    //containters
    JPanel top = new JPanel();
    JPanel middle = new JPanel();
    JPanel bottom = new JPanel();
    //components on container in NORTH
    JLabel taxRept = new JLabel("TAX REPORT");
    //components on container in CENTER
    JLabel taxYearLabel = new JLabel("Tax Year:");
    JLabel taxYear = new JLabel();
    JLabel toolsBoughtLabel = new JLabel("Total Tools Bought:");
    JLabel toolsBought = new JLabel();
    JLabel toolsDollarsLabel = new JLabel("Total Tool Dollars");
    JLabel toolsDollars = new JLabel();
    //components on containter in SOUTH
    JButton total = new JButton("Display Totals");
    JButton printButton = new JButton("Print");
    
    
    /** Creates a new instance of TaxReport */
    public TaxReport() 
    {
       super();
       setSize(400,400);
       setLocation(20,20);
       //component added to NORTH
       top.add(taxRept);
       //components added to CENTER
       middle.add(taxYearLabel);
       middle.add(taxYear);
       middle.add(toolsBoughtLabel);
       middle.add(toolsBought);
       middle.add(toolsDollarsLabel);
       middle.add(toolsDollars);
       //components added to SOUTH
       bottom.add(total);
       total.addActionListener(this);
       bottom.add(printButton);
       printButton.addActionListener(this);
       //containers on JPanel
       add(top);
       add(middle,new GridLayout(5,2));
       add(bottom);
    }
    
    public void actionPerformed(ActionEvent e) {
    }
    
}