Clearing the Tileset in a ResourceTileControlWidget/AutotileBrushControlWidget sets the value to null Created ReferencedResourceWidget which the two controls now derive from TileResource.Tile now implements IJsonConvert, only serializing info necessary to complete the reference. Fix TileAtlas error Fix NREs in AutotileTileControl Fix another TileAtlas oversight Refactored TilesetResource.Tile. TilesetResource has it's own JsonConverter to ensure data is serialized in it's entirety in the resource but not elsewhere (references) Fix TilesetResource.AddTile and TilesetResource.RemoveTile Make TilesetResource.TileMap internal and add TilesetResource.GetTileFromId