Load the attached fxml (using FXMLLoader.load() or SB 2.0).
- Open the Properties TitledPane, and move the scrollbar until getting the "MenuButton Issue..." row.
- Click on the arrow MenuButton: OK
- Click in the textfield on its left, and enter "a"
- Click again on the arrow MenuButton: the popup appears very far below the MenuButton: bug

You can note that surprisingly as soon as the text field is empty, the MenuButton popup is displayed correctly.