code: protected void registerItem(I item) {
  
          if (item.getId() != null) {
              m_items.put(item.getId(), item);
          }
          if (m_tmPrefix != null) {
              item.truncate(m_tmPrefix, m_childWidth);
          }
      }
docs: Registers the given item on this list.<p>
  
  @param item the item to register