code: public void insertChild(CmsTreeItem item, int position) {
  
          m_children.insert(item, position);
          adopt(item);
      }
docs: Inserts the given item at the given position.<p>
  
  @param item the item to insert
  @param position the position
  
  @see org.opencms.gwt.client.ui.CmsList#insertItem(org.opencms.gwt.client.ui.I_CmsListItem, int)