code: public static CSSFXConfig onlyFor(Scene s) {
          CSSFXConfig cfg = new CSSFXConfig();
          cfg.setRestrictedToScene(s);
          return cfg;
      }
docs: Restrict the source file detection for graphical sub-tree of the given {@link Scene}
  
  @param s the scene to restrict the detection on, if null then no restriction will apply
  @return a {@link CSSFXConfig} object as a builder to allow further configuration