[SWING] Un layout dentro un altro

        // bottone di aggiunta
        JButton add = new JButton(" Add ");
        // pan
        areaBox = new JPanel( new GridBagLayout() );
        areaBox.setVisible(true);
        // GridBagLayout
        final GridBagConstraints gc = new GridBagConstraints();
        gc.gridx = 0;
        gc.gridy = 0;
        gc.anchor = GridBagConstraints.WEST;
        panel = new JPanel( new GridBagLayout() );
        
        gc.gridx = 0;
        gc.gridy = 0;
        gc.fill = GridBagConstraints.NONE;
        panel.add(add, gc);
        
        gc.gridx = 0;
        gc.gridy = 1;
        gc.fill = GridBagConstraints.NONE;
        panel.add(areaBox, gc);
        
        add.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent addEvent){
            	try{
            		// aggiunta dell'ultimo job
            		panel.add( nuovoPanSettatoConGridBagLayout, gc);    // <------ Aggiunta panel settato con GridBagLayout
            		areaBox.repaint();
            		
            		getContentPane().revalidate();
            		getContentPane().repaint();
            		pack();    // <------ errore ???
            	}
            	catch ( Exception err ){
            		err.printStackTrace();
            	} 
            }
        }); 
        
        pack();

java.lang.IllegalArgumentException: illegal anchor value
	at java.awt.GridBagLayout.AdjustForGravity(GridBagLayout.java:1763)
        ....