protected void SetupViewport()
        {
            Stage.Color = new Clutter.Color(0x00, 0x00, 0x00, 0xff);
            cover_manager.SetRotation(RotateAxis.X, viewportAngleX, Stage.Width / 2, Stage.Height / 2, 0);
            Stage.Add(cover_manager);

            cover_manager.EmptyActor.SetToPb(
                IconThemeUtils.LoadIcon(cover_manager.TextureSize, "gtk-stop", "clutterflow-large.png")
                );
            CoverManager.DoubleClickTime = (uint)Gtk.Settings.GetForScreen(this.Screen).DoubleClickTime;
            cover_manager.LowerBottom();
            cover_manager.Show();
        }