code: private void uncheckAll(CmsList<? extends I_CmsListItem> list) {
  
          for (Widget it : list) {
              CmsTreeItem treeItem = (CmsTreeItem)it;
              treeItem.getCheckBox().setChecked(false);
              uncheckAll(treeItem.getChildren());
          }
      }
docs: Uncheck all items in the list including all sub-items.
  @param list list of CmsTreeItem entries.