code: public static ScrollableArea create(@Nullable final Area top, @Nullable final Area bottom) {
          return new ScrollableArea(top, bottom);
      }
docs: Creates and returns a new scrollable area.
  
  @param top
  The top-most area, which should be scrollable, as a value of the enum {@link Area} or
  null, if no area should be scrollable
  @param bottom
  The bottom-most area, which should be scrollable, as a value of the enum {@link
  Area}. If the top-most area is null, the bottom-most are must be null as well. The
  index of the bottom-most area must be at least the index of the top-most area