code: public static SceneToggler register(Stage stage, Parent parent) {
          final SceneToggler toggler = new SceneToggler(stage, parent);
          stage.addEventFilter(KeyEvent.KEY_PRESSED, toggler);
          return toggler;
      }
docs: Register a {@link SceneToggler} as an event filter with the {@link Stage}.
  Will toggle on the default key combination of Ctrl+`
  
  @param stage Stage to register on.
  @param parent The parent to show upon toggle.
  @return The sceneToggler, in case a different key combination is desired.
  
  @see #setToggleCombination(KeyCombination)