Don't ever return NaN from getLayerContainerPxFromViewPortPx, since that

can cause problems in multiple different layers -- instead, just return 
null, which is handled more gracefully.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@1219 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Map.js

@@ -1008,7 +1008,10 @@ OpenLayers.Map.prototype = {
             var dY = -parseInt(this.layerContainerDiv.style.top);
             layerPx = viewPortPx.add(dX, dY);
         }
-        return layerPx;
+        if (!isNaN(layerPx.x) && !isNaN(layerPx.y)) {
+            return layerPx;
+        }
+        return null;
     },
     
   //