This code reproduce issue (Press TAB several times)
@Override
    public void start(Stage stage) throws Exception {
        VBox root = new VBox(15);
        MenuBar menuBar = MenuBarBuilder.create().menus(MenuBuilder.create().
                items(new MenuItem("Item")).text("File").build()).build();
        menuBar.setFocusTraversable(true);
        root.getChildren().addAll(new Button("First"),
                 menuBar
                , new Button("Second"));
        Scene scene = new Scene(root, 200, 200);
        stage.setScene(scene);
        stage.setTitle(VersionInfo.getRuntimeVersion());
        stage.show();
    }