How to create popup menu

I am newbie on javafx. I want to show popup menu on Right Mouse click. I find one tutorial Here and Here but don't understand. I want to create popup menu which show in image on this link.

Right now i am creating stage but i don't want stage. I need to show popup menu which show on right click and close when i click anywhere.

Here is my code in which i am using stage but i need to ope popup menu like above link.

 public void MouseClickedOnTree(MouseEvent event) {
if (event.isSecondaryButtonDown()) {

        System.out.println("secondary press");
        final Stage optionstage = new Stage();

        VBox vBox = new VBox(5);
        vBox.setMinHeight(50);
        vBox.setMinWidth(50);
        Button btnNewTestBed = new Button("New Testbed");
        btnNewTestBed.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                try {
                     optionstage.close();
                    stage.show();
                } catch (IOException ex) {
                    Exceptions.printStackTrace(ex);
                }
            }
        });
        Button btnOpenTestbed = new Button("Open Testbed");
        btnOpenTestbed.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                optionstage.close();

            }
        });
        optionstage.addEventHandler(KeyEvent.KEY_PRESSED, new EventHandler<KeyEvent>() {
            @Override
            public void handle(KeyEvent t) {
                if (t.getCode() == KeyCode.ESCAPE) {
                    System.out.println("click on escape");
                    //Stage sb = (Stage) label.getScene().getWindow();//use any one object
                    if(optionstage.isShowing())
                        optionstage.close();
                }
            }
        });

        vBox.getChildren().addAll(btnNewTestBed, btnOpenTestbed);
        optionstage.setScene(new Scene(vBox, 100, 100));
        //stage.setScene(new Scene(new Group(new Text(50,50, "my second window")))); 
        optionstage.setX(event.getSceneX());
        optionstage.setY(event.getScreenY());
        optionstage.initStyle(StageStyle.UNDECORATED);
        optionstage.show();

    }

Please provide me any link or reference.