super(key, delegate, ancestor);
    }

    List<V> getListDelegate() {
      return (List<V>) getDelegate();
    }

    @Override
    public boolean addAll(int index, Collection<? extends V> c) {
      if (c.isEmpty()) {
        return false;
      }
      int oldSize = size(); // calls refreshIfEmpty
      boolean changed = getListDelegate().addAll(index, c);
      if (changed) {