@Nullable
      @Override
      public String getLocationString() {
        if (!isValid()) {
          return null;
        }
        if (getCompositeChildren().size() == 0) {
          return shrinkTextTo(PRESENTABLE_TEXT_LENGTH);
        }
        else {
          return null;
        }
      }
@Nullable
      @Override
      public String getLocationString()