code: protected void adopt(final CmsTreeItem item) {
  
          item.setParentItem(this);
          item.setTree(m_tree);
          onChangeChildren();
          if ((m_tree != null) && m_tree.isAnimationEnabled()) {
              // could be null if not yet attached
              item.getElement().getStyle().setOpacity(0);
              // animate
              (new Animation() {
  
                  /**
                   * @see com.google.gwt.animation.client.Animation#onUpdate(double)
                   */
                  @Override
                  protected void onUpdate(double progress) {
  
                      item.getElement().getStyle().setOpacity(progress);
                  }
              }).run(ANIMATION_DURATION);
          }
      }
docs: Adopts the given item.<p>
  
  @param item the item to adopt