Layout Manager Problme

import java.awt.*;
import java.awt.event.*;
import javax.swing.*; 
....
private void createGUI()
    {
        JFrame win = new JFrame("4 gewinnt");
        win.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        createMenu();
        createPlField(win.getContentPane());


        win.pack();
        win.setSize(res_x, res_y);
        win.setVisible(true);
     }
private void createMenu()
    {
        JMenuBar menubar = new JMenuBar();
        menubar.add(createFileMenu());
        menubar.add(createGameMenu());
        menubar.add(createControlMenu());
        setJMenuBar(menubar);
    }
private void createPlField(Container wind)
    {
        BitmapComponent img;
        GridBagLayout gbl = new GridBagLayout();
        wind = setLayout(gbl);
        GridBagConstraints gbc = new GridBagConstraints();
        img = new BitmapComponent("Feld.png");
        gbc.gridx = 0;
        gbc.gridy = 0;
        wind.add(img, gbc);


        img = new BitmapComponent("Feld.png");
        gbc.gridx = 1;
        gbc.gridy = 0;
        wind.add(img, gbc);


    }