MousePosition control throws error when no layers are on map. Fix it so that

they don't. Thanks for the review, fredj. Includes tests. (Closes #1029)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@5371 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Control/MousePosition.js

@@ -108,6 +108,10 @@ OpenLayers.Control.MousePosition = OpenLayers.Class(OpenLayers.Control, {
             }
 
             lonLat = this.map.getLonLatFromPixel(evt.xy);
+            if (!lonLat) { 
+                // map has not yet been properly initialized
+                return;
+            }    
             this.lastXy = evt.xy;
         }