@Override
    @Nullable
    public Integer getNodeIndex(int nodeId) {
      assertNotUnderModification();
      Integer delegateIndex = myDelegatedGraph.getNodeIndex(nodeId);
      if (delegateIndex == null) return null;
      if (myDelegateNodesVisibility.isVisible(delegateIndex)) {
        return myNodesMap.getShortIndex(delegateIndex);
      }
      else {
        return null;
      }
    }
@Override
    @Nullable
    public Integer getNodeIndex(int nodeId)