anchor.diff:      return;
     }
     bench = new Bench(parsedGame.player1, parsedGame.player2);
  -  validMoves = [];
  +  selectedPiece = null;
     gamestate.initialize(parsedGame.gameEvents);
     gamestate.step(1);
     render(gamestate);
   }
   
   void showNextMove(GameState gamestate) {
  -  validMoves = [];
  +  selectedPiece = null;
     gamestate.stepBy(1);
   
     render(gamestate);
   }
   
   void showPreviousMove(GameState gamestate) {
  -  validMoves = [];
  +  selectedPiece = null;
     gamestate.stepBy(-1);
   
     render(gamestate);
   }
   
   void showFirstMove(GameState gamestate) {
  -  validMoves = [];
  +  selectedPiece = null;
     gamestate.step(1);
   
     render(gamestate);
   }
   
   void showLastMove(GameState gamestate) {
  -  validMoves = [];
  +  selectedPiece = null;
     gamestate.stepToEnd();
   
     render(gamestate);
  
positive.code: 
  var camera = new Camera();
  Bench bench;
  List<Move> validMoves = [];
  
  
  void main() {
  
negative.code: }
  
  void handleKeyPress(KeyboardEvent event, GameState gamestate) {
    selectedPiece = null;
  
    switch (event.keyCode) {
      case 37: //left
  