Run this code
@Override
    public void start(Stage stage) throws Exception {
        HBox pane = new HBox(20);
        MenuButton menuButton = new MenuButton("MenuButton");
        menuButton.getItems().addAll(new MenuItem("Item 1"));
        menuButton.setFocusTraversable(false);
        pane.getChildren().addAll(new Button("Button"), menuButton, new Button("Button"));
        Scene scene = new Scene(pane, 300, 300);
        stage.setScene(scene);
        stage.setTitle(VersionInfo.getRuntimeVersion());
        stage.show();
    }
press TAB several times - MenuButton though not allocated active - focus on it