private void loadSubControllers() throws IOException {
    for (final String key : this.optionsViews.keySet()) {
      final ContentController controller = loadSubController(this.optionsViews.get(key));
      if (controller != null) {

        this.controllers.add(controller);

        this.component.getChildren().add(controller.getRootNode());
        controller.getRootNode().setVisible(false);

        controller.setName(key);

        ////
        final Button buttonNav = new Button(key);
        buttonNav.getStyleClass().add("nav-button");
        buttonNav.getStyleClass().add("xine-button");
        buttonNav.setPrefHeight(49);
        buttonNav.setOnAction(
            e -> {
              activeController(controller);
            });

        ////

        controller.setNavigationButton(buttonNav);
        this.navItems.getChildren().add(controller.getNavigationButton());

        // this.component.getChildren().add(controller.getRootNode());
      }
    }
  }
 public OfficeController() {
   super.setName("Office");
 }