First run - focus set for "Title 2", but press TAB key several times he breaks between buttons 1 and 2
if i click any titles - it's remove this problem.
 @Override
    public void start(Stage stage) throws Exception {
        FlowPane root = new FlowPane();
        Scene scene = new Scene(root, 250, 200);
        Accordion accordion = AccordionBuilder.create().panes(
                    TitledPaneBuilder.create().content(new Button("Ok")).focusTraversable(false).text("Title 1").build(),
                    TitledPaneBuilder.create().content(new Button("Ok")).text("Title 2").build(),
                    TitledPaneBuilder.create().content(new Button("Ok")).text("Title 3").build(),
                    TitledPaneBuilder.create().content(new Button("Ok")).text("Title 4").build(),
                    TitledPaneBuilder.create().content(new Button("Ok")).text("Title 5").build(),
                    TitledPaneBuilder.create().content(new Button("Ok")).text("Title 6").build()
                ).build();
        root.getChildren().addAll(new Button("1"), accordion, new Button("2"));
        stage.setScene(scene);
        stage.setTitle(VersionInfo.getRuntimeVersion());
        stage.show();
    }