public override bool Initialize()
            {
                viewer = GameViewer.Instance;
                if (viewer == null)
                    return false;

                viewer.RegisterPrintHandler (this);

                ImageMenuItem item =
                    new ImageMenuItem (Catalog.
                               GetString
                               ("_PS File"));
                  item.Image =
                    new Image (Gtk.Stock.SaveAs,
                           IconSize.Menu);
                  exportPsMenuItem = item;
                  exportPsMenuItem.Activated +=
                    on_export_ps_activate;
                  exportPsMenuItem.Show ();
                  viewer.RegisterExporter (this,
                               exportPsMenuItem);
                  return true;
            }