diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index cf7780a7b3..5b98147b32 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -61,7 +61,8 @@ OpenLayers.Layer.Grid.prototype = Object.extend( new OpenLayers.Layer(), {
      * @deprecated User should just set the 'tileSize' via options
      */
     setTileSize: function (size) {
-        this.tileSize = size.copyOf();
+        if (size)
+            this.tileSize = size.copyOf();
     },
 
     /** This function is called whenever the map is moved. All the moving
diff --git a/lib/OpenLayers/Layer/WFS.js b/lib/OpenLayers/Layer/WFS.js
index 9bf64f31d7..6e85f6e920 100644
--- a/lib/OpenLayers/Layer/WFS.js
+++ b/lib/OpenLayers/Layer/WFS.js
@@ -88,7 +88,8 @@ OpenLayers.Layer.WFS.prototype =
         Object.extend(mergedParams, this.params);
         Object.extend(mergedParams, params);
         var obj = new OpenLayers.Layer.WFS(name, this.url, mergedParams);
-        obj.setTileSize(this.tileSize);
+        if (this.tileSize)
+            obj.setTileSize(this.tileSize);
         return obj;
     },