Applet only runs 50% of the time in Netbeans

Question

I run this application and 50% of the time it works and the other half it doesn't. I'm not changing any code and I noticed this happens w/ my SSCCE and the actual program. I'm using Netbeans, I right click the file and choose run.
Here's the SSCCE:
package carbuyer;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.TitledBorder;
public class SampleApplet extends JApplet implements ActionListener {
    private JTextField jtfSellingPrice = new JTextField();
    private JButton jbtComputeCost = new JButton("Compute Cost");
@Override
public void init() {
        //Right align text fields
        jtfSellingPrice.setHorizontalAlignment(JTextField.RIGHT);
        //Panel p1 to hold labels and text fields
        JPanel p1 = new JPanel();
        p1.setLayout(new GridLayout(5,2));
        p1.add(new Label("Selling Price: "));
        p1.add(jtfSellingPrice);
        p1.setBorder(new TitledBorder("Enter Selling price, trade in value, down payment, APR, and loan term"));
        //Panel p2 to hold the button
        JPanel p2 = new JPanel();
        p2.setLayout(new FlowLayout(FlowLayout.RIGHT));
        p2.add(jbtComputeCost);
        //Add the components to the applet
        getContentPane().add(p1,BorderLayout.CENTER);
        getContentPane().add(p2,BorderLayout.SOUTH);
        //Register listener
        jbtComputeCost.addActionListener(this);
                try {
            java.awt.EventQueue.invokeAndWait(new Runnable() {
                public void run() {
                    initComponents();
        } catch (Exception ex) {
            ex.printStackTrace();
/**Handle the ComputeCost button */
    public void actionPerformed(ActionEvent e)
    /** This method is called from within the init() method to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {
        setLayout(new java.awt.BorderLayout());
    }// </editor-fold>
    // Variables declaration - do not modify
    // End of variables declaration
}

Answer 1

Here's my SSCCE to demonstrate the problem that occurs when you set the contentPane's layout to BorderLayout after adding components:
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class SampleSwing {
  private static void createAndShowGUI() {
    JPanel mainPanel = new JPanel();
    mainPanel.add(new JButton("Fubar"));
    JFrame frame = new JFrame("SampleSwing Application");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add(mainPanel);
    // Comment and uncomment the following line to see its effect:
    //frame.getContentPane().setLayout(new BorderLayout());
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  public static void main(String[] args) {
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        createAndShowGUI();
}