anchor.diff:  
       type FieldDispatcher () =
           inherit ScreenDispatcher<FieldModel, FieldMessage, FieldCommand> (FieldModel.initial)
  +
  +        static let pageItems pageSize pageIndex items =
  +            items |>
  +            Seq.chunkBySize pageSize |>
  +            Seq.trySkip pageIndex |>
  +            Seq.map List.ofArray |>
  +            Seq.tryHead |>
  +            Option.defaultValue []
   
           static let isFacingBodyShape bodyShape (avatar : AvatarModel) world =
               if bodyShape.Entity.Is<PropDispatcher> world then
  
positive.code:                         (fun (shopModelOpt, inventory : Inventory) _ ->
                              match shopModelOpt with
                              | Some shopModel ->
                                  inventory |>
                                  Inventory.indexItems |>
                                  Seq.choose
                                      (function
                                       | (_, Equipment _ as item) | (_, Consumable _ as item) -> Some item
                                       | (_, KeyItem _) | (_, Stash _) -> None) |>
                                  Seq.chunkBySize 10 |>
                                  Seq.trySkip shopModel.ShopPage |>
                                  Seq.map List.ofArray |>
                                  Seq.tryHead |>
                                  Option.defaultValue []
                              | None -> [])
                          (fun i selection _ ->
                              let x = if i < 5 then 12.0f else 448.0f
  
negative.code:                     match shopModel.ShopConfirmModelOpt with
                      | Some shopConfirmModel ->
                          let itemType = snd shopConfirmModel.ShopConfirmSelection
                          let model =
                              FieldModel.updateInventory
                                  (match shopModel.ShopState with
                                   | ShopBuying -> Inventory.addItem itemType
                                   | ShopSelling -> Inventory.removeItem itemType)
                                  model
                          let model =
                              FieldModel.updateInventory
                                  (match shopModel.ShopState with
                                   | ShopBuying -> Inventory.updateGold (fun gold -> gold - shopConfirmModel.ShopConfirmPrice)
                                   | ShopSelling -> Inventory.updateGold (fun gold -> gold + shopConfirmModel.ShopConfirmPrice))
                                  model
                          let model =
                              FieldModel.updateShopModelOpt (Option.map (fun shopModel ->
                                  { shopModel with ShopConfirmModelOpt = None }))
                                  model
                          withCmd model (PlaySound (0L, Constants.Audio.DefaultSoundVolume, Assets.PurchaseSound))
                      | None -> just model
                  | None -> just model
  