diff --git a/lib/OpenLayers/Layer/WMS/Untiled.js b/lib/OpenLayers/Layer/WMS/Untiled.js
index 23e1cea2fd..9536e0aa64 100644
--- a/lib/OpenLayers/Layer/WMS/Untiled.js
+++ b/lib/OpenLayers/Layer/WMS/Untiled.js
@@ -125,7 +125,7 @@ OpenLayers.Layer.WMS.Untiled.prototype =
 
             //clear out the old tile 
             if (this.tile) {
-                OpenLayers.Util.clearArray(this.tile);
+                this.tile.clear();
             }
 
             //determine new tile bounds
@@ -150,6 +150,11 @@ OpenLayers.Layer.WMS.Untiled.prototype =
             var ul = new OpenLayers.LonLat(tileBounds.left, tileBounds.top);
             var pos = this.map.getLayerPxFromLonLat(ul);
 
+            if ( this.tile && !this.tile.size.equals(tileSize)) {
+                this.tile.destroy();
+                this.tile = null;
+            }
+
             if (!this.tile) {
                 this.tile = new OpenLayers.Tile.Image(this, pos, tileBounds, 
                                                      url, tileSize);
diff --git a/lib/OpenLayers/Map.js b/lib/OpenLayers/Map.js
index 2116c2f9bf..11f69950bc 100644
--- a/lib/OpenLayers/Map.js
+++ b/lib/OpenLayers/Map.js
@@ -786,8 +786,10 @@ OpenLayers.Map.prototype = {
         var originPx = this.getViewPortPxFromLonLat(this.layerContainerOrigin);
         var newPx = this.getViewPortPxFromLonLat(lonlat);
 
-        this.layerContainerDiv.style.left = (originPx.x - newPx.x) + "px";
-        this.layerContainerDiv.style.top  = (originPx.y - newPx.y) + "px";
+        if ((originPx != null) && (newPx != null)) {
+            this.layerContainerDiv.style.left = (originPx.x - newPx.x) + "px";
+            this.layerContainerDiv.style.top  = (originPx.y - newPx.y) + "px";
+        }
     },
 
     /**