How to refresh JInternalFrame or JPanel form on button click where JPanel is a separate class and used in JInternalFrame

Iam trying to build a desktop application with multiple screens inside one single JFrame. So each button click event will take us to the separate screen with refreshed components in the screen. So far this approach is working for me but the problem I am facing is even after using ".dispose(), .repaint(), .revalidate(), .invalidate()" functions. JInternalFrame or Jpanel seems to not refresh its components.

Which works something like below gif.

Tabbed Style

I do know JtabbedPane exists but for my method JtabbedPane is not viable.

Below I am posting minified code by replicating the problem I am facing.

MainMenu.Java(file with Main Class)

package test;

import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JScrollPane;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JInternalFrame;

public class MainMenu extends JFrame {

    private JPanel contentPane;
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MainMenu frame = new MainMenu();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
    public MainMenu() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 841, 522);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);
        
        JPanel panel = new JPanel();
        panel.setBounds(10, 10, 807, 63);
        contentPane.add(panel);
        panel.setLayout(new GridLayout(1, 0, 0, 0));
        
        JButton Tab1 = new JButton("Tab1");
        panel.add(Tab1);
        
        JButton Tab2 = new JButton("Tab2");
        panel.add(Tab2);
        
        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setBounds(10, 88, 807, 387);
        contentPane.add(scrollPane);
        
        JInternalFrame internalFrame1 = new JInternalFrame();
        JInternalFrame internalFrame2 = new JInternalFrame();
        
        Tab1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Panel1 panel1 = new Panel1();
                if(internalFrame1 !=null) {
                    internalFrame1.dispose();
                    panel1.invalidate();
                    panel1.revalidate();
                    panel1.repaint();
                }
                internalFrame1.setTitle("Panel 1");
                scrollPane.setViewportView(internalFrame1);
                internalFrame1.getContentPane().add(panel1);
                internalFrame1.setVisible(true);
                
            }
        });
        
        Tab2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Panel2 panel2 = new Panel2();
                if(internalFrame2 !=null) {
                    internalFrame2.dispose();
                    panel2.invalidate();
                    panel2.revalidate();
                    panel2.repaint();
                }
                internalFrame2.setTitle("Panel 2");
                scrollPane.setViewportView(internalFrame2);
                internalFrame2.getContentPane().add(panel2);
                internalFrame2.setVisible(true);
            }
        });
    }
}

and the corresponding Jpanel class files where JInternal Frames Panel1.java

package test;

import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JButton;

public class Panel1 extends JPanel {
    private JTextField textField;

    /**
     * Create the panel.
     */
    public Panel1() {
        setLayout(null);
        
        textField = new JTextField();
        textField.setBounds(10, 60, 430, 19);
        add(textField);
        textField.setColumns(10);
        
        JButton btnNewButton = new JButton("Example Button");
        btnNewButton.setBounds(10, 156, 430, 21);
        add(btnNewButton);

    }
}

Panel2.java

package test;

import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JButton;

public class Panel2 extends JPanel {
    private JTextField textField;

    /**
     * Create the panel.
     */
    public Panel2() {
        setLayout(null);
        
        textField = new JTextField();
        textField.setBounds(10, 60, 430, 19);
        add(textField);
        textField.setColumns(10);
        
        JButton btnNewButton = new JButton("New button2");
        btnNewButton.setBounds(21, 157, 419, 21);
        add(btnNewButton);

    }
}

P.S: This is my first time asking question in Stackoverflow so forgive me and if possible guide me if i miss anything

Thank you :)

Edit: The problem I am facing is on the surface it looks like the Jpanel has been refreshed but the components like JtextField Still hides the previously written text in it and only show the text when i click on that JTextField

Below I am Attaching another gif which show highlights the issue. I have highlighted the part where I am facing issue.

Issue I am Facing

The dispose() method does not remove components so you keep adding components to the internal frame when you use the following:

internalFrame1.getContentPane().add(panel1);

Instead you might do something like:

Container contentPane = internalFrame1.getContentPane();
contentPane.removeAll();
contentPane.add( panel1 );
contentPane.revalidate();
contentPane.repaint();