Button sortButton = new Button();

private void initForm()
{
        sortButton.setDock(ControlDock.BOTTOM);
        sortButton.setLocation(new Point(0, 277));
        sortButton.setSize(new Point(300, 23));
        sortButton.setTabIndex(0);
        sortButton.setText("Sort");
        sortButton.addOnClick(new EventHandler(this.sortClick));
        
        /*Download complete sample for full code */       
}

private void sortClick(Object source, Event e)
{
        m_pDlg = new ProgressDialog();
        m_pDlg.show();
        m_pDlg.progressBar.setMaximum( m_items.length );
        
        m_items = m_app.sortItems( m_items );
        
        showItems();
}