public   static   void  main(String[] args) {
        Display display =  new  Display();
        Shell shell =  new  Shell(display);
        shell.setLayout( new  FillLayout());
         final  Composite composite =  new  Composite(shell, SWT.NONE);
        composite.setLayout( new  RowLayout());
         final  Group group1 =  new  Group(composite, SWT.NONE);
        group1.setText("group1");
        Button button =  new  Button(composite, SWT.NONE);
        button.setText("change group");
        button.addSelectionListener( new  SelectionAdapter() {
             public   void  widgetSelected(SelectionEvent arg0) {
                 if  (!group1.isDisposed()) {
                    group1.dispose();
                    Group group2 =  new  Group(composite, SWT.NONE);
                    group2.setText("group2");
                    composite.layout();
                }
            }
        });
        shell.open();
         while  (!shell.isDisposed()) {
             if  (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }