anchor.diff:  
           // track registration
           if unregistered then
  -            registrations.Remove entityId |> ignore<bool>
  -            unregistrations.Add entityId |> ignore<bool>
  +            changes.Add struct (entityId, false)
   
           // unregister correlation
           if unregistered && not isolated then
  
positive.code:         let nodeIdStr = string nodeId
          systemTree |>
          ListTree.findAll (fun system -> system.Name = nodeIdStr) |>
          Seq.iter (fun system -> system.GetEntitiesCorrelated () |> Seq.iter (fun correlated -> system.UnregisterCorrelated correlated |> ignore<bool>))
          systemDict.Remove nodeId
  
      member this.QualifyHierarchical nodeId entityId =
  
negative.code:         systemTree |> ListTree.map (fun system -> system.WithCorrelatedsBuffered fn worldOpt)
  
      member this.PopHierarchyChanges () =
          let popped = changes
          changes <- List<struct (Guid * bool)> ()
          popped
  
      member this.IndexNode nodeId =
          match systemDict.TryGetValue nodeId with
  