The method TilemapLayer.weightedRandomize has changed so that the parameter weightedIndexes is now first in the method and is non-optional. Previously, it was the 5th parameter and incorrectly flagged as optional. This change was made to the docs but not the parameters, but now works according to the docs

Author: photonstorm

src/tilemaps/TilemapLayer.js

@@ -1200,7 +1200,7 @@ var TilemapLayer = new Class({
      *
      * @return {this} This Tilemap Layer object.
      */
-    weightedRandomize: function (tileX, tileY, width, height, weightedIndexes)
+    weightedRandomize: function (weightedIndexes, tileX, tileY, width, height)
     {
         TilemapComponents.WeightedRandomize(tileX, tileY, width, height, weightedIndexes, this.layer);