code: public static ScrollBar findScrollBar(Parent parent, Orientation orientation) {
          for (Node node : parent.getChildrenUnmodifiable()) {
              if (node instanceof ScrollBar) {
                  ScrollBar b = (ScrollBar) node;
                  if (b.getOrientation().equals(orientation)) {
                      return b;
                  }
              }
  
              if (node instanceof Parent) {
                  ScrollBar b = findScrollBar((Parent) node, orientation);
                  if (b != null) {
                      return b;
                  }
              }
          }
  
          return null;
      }
docs: Searches for a {@link ScrollBar} of the given orientation (vertical, horizontal)
  somewhere in the containment hierarchy of the given parent node.
  
  @param parent      the parent node
  @param orientation the orientation (horizontal, vertical)
  @return a scrollbar or null if none can be found