docs: protected void updateRealSelection(Set<Object> selectionEventIds) {
  
          Set<Object> pageItems = Sets.newHashSet(m_table.get().getContainerDataSource().getItemIds());
          Set<Object> result = Sets.newHashSet(m_realSelection);
          result.removeAll(pageItems);
          result.addAll(selectionEventIds);
          m_realSelection = result;
  
      }