anchor.diff:                  getFreshKeyAndValueEntity <- Unchecked.defaultof<Entity>
                   getFreshKeyAndValueWorld <- Unchecked.defaultof<World>
                   match entityStateOpt :> obj with
  -                | null -> Unchecked.defaultof<EntityState>
  +                | null ->
  +                    Unchecked.defaultof<EntityState>
                   | _ ->
  -                    if entityStateOpt.ShouldMutate then entity.EntityStateOpt <- entityStateOpt
  +                    if entityStateOpt.ShouldMutate then
  +                        entityStateOpt.Invalidated <- false
  +                        entity.EntityStateOpt <- entityStateOpt
                       entityStateOpt
               else entityStateOpt
   
  
positive.code:                 // add entity to world
                  let world = World.addEntityState entityState entity world
  
                  // mutate entity tree
                  let world =
                      if WorldModule.isSelected entity world then
                          let entityTree =
  
negative.code: 
          static member internal updateEntityInEntityTree oldOmnipresent oldAbsolute oldBoundsMax (entity : Entity) oldWorld world =
  
              // only do this when entity is selected
              if WorldModule.isSelected entity world then
  
                  // OPTIMIZATION: work with the entity state directly to avoid function call overheads
  