anchor.diff:              if changed then
                   // HACK: we need to use content key for an additional purpose, so we add 2 (key with add 1 may already be used in invoking function).
                   // TODO: make sure our removal of this key's entry is comprehensive or has some way of not creating too many dead entries.
  -                let contentKeyPlus2 = Gen.idDeterministic 2 contentKey
  +                let contentKeyPlus2 = Gen.idDeterministic 2 contentKey // ELMISH_CACHE
                   let world = World.removeSynchronizedSimulants contentKeyPlus2 removed world
                   let world = World.addSynchronizedSimulants contentMapper contentKeyPlus2 mapGeneralized added origin owner parent world
                   let world = World.addKeyedValue contentKey current world
  
positive.code:                             let mapGeneralized = Lens.getWithoutValidation binding.CBSource world
                              let currentKeys = mapGeneralized.Keys
                              let previousKeys =
                                  match World.tryGetKeyedValueFast<IComparable List> (contentKeyPlus1, world) with
                                  | (false, _) -> List ()
                                  | (true, previous) -> previous
                              if not (currentKeys.SequenceEqual previousKeys) then
                                  let world = World.addKeyedValue contentKeyPlus1 currentKeys world
                                  let current = World.makeLensesCurrent currentKeys binding.CBSource world
                                  World.synchronizeSimulants binding.CBMapper binding.CBContentKey mapGeneralized current binding.CBOrigin binding.CBOwner binding.CBParent world
                              else world
                          else 
                              let config = World.getCollectionConfig world
                              let lensesCurrent = USet.makeEmpty (LensComparer ()) config
                              let world = World.synchronizeSimulants binding.CBMapper binding.CBContentKey (MapGeneralized.make Map.empty) lensesCurrent binding.CBOrigin binding.CBOwner binding.CBParent world
  
negative.code: 
      /// The default screen - may or may not exist.
      let DefaultScreen = Screen "Screen"
  
      /// The default group - may or may not exist.
      let DefaultGroup = DefaultScreen / "Group"
  
      /// The default entity - may or may not exist.
      let DefaultEntity = DefaultGroup / "Entity"
  
  