code: public void showSlideMenu() {
          synchronized (this) {
              if (!this.menuShown.getAndSet(true)) {
                  final SlideMenuModel smm = getModel(Key.create(SlideMenuModel.class, this.selectedSlide));
  
                  StackPane.setAlignment(smm.node(), Pos.CENTER);
                  view().node().getChildren().add(smm.node());
  
                  smm.node().parentProperty().addListener((observable, oldValue, newValue) -> {
                      if (newValue == null) {
                          this.menuShown.set(false);
                      }
                  });
              }
          }
      }
docs: Display the slide menu to navigate.