private @NotNull ExtendMode calcExtendMode(int index) {
      ListPopupStep<Object> listStep = getListStep();
      Object selectedValue = myListModel.getElementAt(index);
      if (selectedValue == null || !listStep.hasSubstep(selectedValue)) return ExtendMode.NO_EXTEND;

      return myShowSubmenuOnHover ? ExtendMode.EXTEND_ON_HOVER : ExtendMode.NO_EXTEND;
    }
private @NotNull ExtendMode calcExtendMode(int index)