i'm not a java guy however i start implementing some security tools with java, in these days i'm creating a gui for my security tools :

Here is the how my Gui looks:

   menuBar = new JMenuBar();              // construct menu bar
   // hash functions
   fileMenu = new JMenu("HASH FUNCTIONS");          // define file menu
   fileMenu.setMnemonic('H');             // shortcut

   hashes = new JMenuItem("Md5&Sha1");     // define file menu options
   hashes.setMnemonic('M');
   hashes.addActionListener(this);
   fileMenu.add(hashes);

   menuBar.add(fileMenu);                 // add file menu to menu bar

   // symmetric encryption
   asMenu = new JMenu("SYMMETRIC ENCRYPTION");      // define format menu
   asMenu.setMnemonic('S');           // shortcut

   desItem = new JMenuItem("DES");   // define format menu options
   desItem.setMnemonic('D');
   desItem.addActionListener(this);
   asMenu.add(desItem);

  ...
  ...

   menuBar.add(helpMenu);                 // add help menu to menu bar

   setJMenuBar(menuBar);                  // put menu bar on application
   textColor = Color.RED;

when from the Menu desitem is selected, desvar is just for not showing the panel multiple times, it calls Panels ()

   else if(e.getSource() == desItem && desvar ==1 )     
   {
       // make other panels unvisible.

       if(hashvar!=1) MyPanel.setVisible(false);//hash functions
       if(rsavar!=1) MyPanel3.setVisible(false);//rsa function
       if (dhvar!=1) MyPanel4.setVisible(false);//dh diffie hellman

       hashvar=1;
       rsavar=1;
       dhvar=1;
       ++desvar;

       desPanel=true;
       Panels();
    }

and in Panels() Method:

if (hashPanel){

        MyPanel.add("West",radioSHA1);
        MyPanel.add("West",radioMD5);
        MyPanel.add("Center", inputField);
        MyPanel.add("East",SubmitButton);

        MyPanel.add("South",resultHash);

        add(MyPanel);
        validate();
        hashPanel=false;
}

i have many panels for example :

-hash functions=mypanel1 , des=mypanel2, rsa functions= mypanel3 , dh= mypanel4

However in may other panals such as rsa function: i have to use some layout properties of the java:in this panel i selected to use gridbaglayout

if (dhPanel){
    System.out.println("rsa panel burda misin");

    MyPanel3.add(pqLabel);
    MyPanel3.add(pLabel);
    MyPanel3.add(pTextArea);
    MyPanel3.add(qLabel);
   ...
   ...
    add(MyPanel3);


generate_pqButton.addActionListener(this);
calculate_nButton.addActionListener(this);
...
    ...
     GridBagLayout layout = new GridBagLayout();
  GridBagConstraints gbc = new GridBagConstraints();
         setLayout(layout);

  // x, y, w, h, wx, wy
  gbc.fill = GridBagConstraints.NONE;
  add (bit_length_label, gbc, 0, 0, 1, 1, 0, 10);
  add (p,         gbc, 0, 1, 1, 1, 0, 10);
  add (g,         gbc, 0, 2, 1, 1, 0, 10);
  add (a,         gbc, 1, 3, 1, 1, 100, 10);
  add (x,         gbc, 0, 4, 1, 1, 0, 10);
  add (gx,        gbc, 0, 5, 1, 1, 0, 10);
  add (gxy,       gbc, 0, 6, 1, 1, 0, 10);
  add (b,         gbc, 1, 7, 1, 1, 100, 10);
  add (y,         gbc, 0, 8, 1, 1, 0, 10);
  add (gy,        gbc, 0, 9, 1, 1, 0, 10);
  add (gyx,       gbc, 0, 10, 1, 1, 0, 10);
  add (sk,        gbc, 1, 11, 1, 1, 100, 10);
  add (key,       gbc, 0, 12, 1, 1, 0, 10);
  add (status,    gbc, 1, 13, 1, 1, 100, 10);
  add (dhstart,     gbc, 1, 14, 1, 1, 100, 10);

  add (bit_length_value, gbc, 1, 0, 1, 1, 100, 10);
  add (p_value,   gbc, 1, 1, 1, 1, 100, 10);
  add (g_value,   gbc, 1, 2, 1, 1, 100, 10);
  add (x_value,   gbc, 1, 4, 1, 1, 100, 10);
  add (gx_value,  gbc, 1, 5, 1, 1, 100, 10);
  add (gxy_value, gbc, 1, 6, 1, 1, 100, 10);
  add (y_value,   gbc, 1, 8, 1, 1, 100, 10);
  add (gy_value,  gbc, 1, 9, 1, 1, 100, 10);
  add (gyx_value, gbc, 1, 10, 1, 1, 100, 10);
    validate();
    repaint();
    rsaPanel=false;
    }

Everthing seems okey however when i swith from one menu to another sometimes components are seen or apper in wrong places or mixed.

where i'm doing wrong?