public Collection<String> getUserIds() {
   synchronized (m_storeLock) {
     return CollectionUtility.hashSet(m_store.keySet());
   }
 }
 @Override
 protected Set<? extends IMenuType> getConfiguredMenuTypes() {
   return CollectionUtility.<IMenuType>hashSet(
       TableMenuType.EmptySpace, TableMenuType.Header, TableMenuType.SingleSelection);
 }
 @Override
 protected Set<? extends IMenuType> getConfiguredMenuTypes() {
   return CollectionUtility.<IMenuType>hashSet(
       TableMenuType.MultiSelection, TableMenuType.SingleSelection);
 }
 @Override
 protected Set<? extends IMenuType> getConfiguredMenuTypes() {
   return CollectionUtility.hashSet(TableMenuType.EmptySpace);
 }