Componentes Swing some ao abrir JFrame maximizado

jfrm_principal.setExtendedState(jfrm_principal.getExtendedState()|JFrame.MAXIMIZED_BOTH);

jfrm_principal.setExtendedState(JFrame.MAXIMIZED_BOTH);

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * jfrm_principal.java
 *
 * Created on 27/10/2010, 09:50:31
 */

package formularios;

import javax.swing.JFrame;

/**
 *
 * @author Carlos
 */
public class jfrm_principal extends javax.swing.JFrame {

    /** Creates new form jfrm_principal */
    public jfrm_principal() {
        initComponents();
    }

    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jmnb_principal = new javax.swing.JMenuBar();
        jmnu_cadastros = new javax.swing.JMenu();
        jmnuItem_clientes = new javax.swing.JMenuItem();
        jMenu2 = new javax.swing.JMenu();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jmnu_cadastros.setText("Cadastro");

        jmnuItem_clientes.setText("Clientes");
        jmnuItem_clientes.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jmnuItem_clientesActionPerformed(evt);
            }
        });
        jmnu_cadastros.add(jmnuItem_clientes);

        jmnb_principal.add(jmnu_cadastros);

        jMenu2.setText("Edit");
        jmnb_principal.add(jMenu2);

        setJMenuBar(jmnb_principal);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 883, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 497, Short.MAX_VALUE)
        );

        pack();
    }// </editor-fold>                        

    private void jmnuItem_clientesActionPerformed(java.awt.event.ActionEvent evt) {                                                  
        new jfrm_clientes().setVisible(true);
    }                                                 

    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                JFrame jfrm_principal = new JFrame();
                /* jfrm_principal.setExtendedState(jfrm_principal.getExtendedState()|JFrame.MAXIMIZED_BOTH);
                Mesmo trocando não funcionou...
                */
                jfrm_principal.setExtendedState(JFrame.MAXIMIZED_BOTH);  
                jfrm_principal.setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JMenu jMenu2;
    private javax.swing.JMenuBar jmnb_principal;
    private javax.swing.JMenuItem jmnuItem_clientes;
    private javax.swing.JMenu jmnu_cadastros;
    // End of variables declaration                   

}