code: Object insertByRightShift(
      int               ix,
      Object            new1)
    {
      Object old1 = null;
      if (isFull())
        {
          old1 = rightMostKey();
          rightMove(ix+1);
          _nodeKey[ix+1] = new1;
        }
      else
        {
          rightShift(ix+1);
          _nodeKey[ix+1] = new1;
          _population++;
          if (midPoint() > rightMostIndex())
            _nodeKey[midPoint()] = rightMostKey();
        }
      return old1;
    }
docs: Insert a new key by shifting keys right.
  
  <p>Insert a new key by overlaying the right-most key, shifting
  other keys right and inserting the new key at the appropriate
  insert point.</p>
  
  @param ix The insert point within the node.
  @param new1 The new key to be inserted.
  @return the key that used to be the right-most key in the node.