diff --git a/lib/OpenLayers/Map.js b/lib/OpenLayers/Map.js
index e545113d2a..cdb1bc01de 100644
--- a/lib/OpenLayers/Map.js
+++ b/lib/OpenLayers/Map.js
@@ -1326,30 +1326,32 @@ OpenLayers.Map = OpenLayers.Class({
      */
     updateSize: function() {
         // the div might have moved on the page, also
-        this.events.clearMouseCache();
         var newSize = this.getCurrentSize();
-        var oldSize = this.getSize();
-        if (oldSize == null) {
-            this.size = oldSize = newSize;
-        }
-        if (!newSize.equals(oldSize)) {
-            
-            // store the new size
-            this.size = newSize;
-
-            //notify layers of mapresize
-            for(var i=0, len=this.layers.length; i<len; i++) {
-                this.layers[i].onMapResize();                
+        if (newSize && !isNaN(newSize.h) && !isNaN(newSize.w)) {
+            this.events.clearMouseCache();
+            var oldSize = this.getSize();
+            if (oldSize == null) {
+                this.size = oldSize = newSize;
             }
-
-            var center = this.getCenter();
-
-            if (this.baseLayer != null && center != null) {
-                var zoom = this.getZoom();
-                this.zoom = null;
-                this.setCenter(center, zoom);
+            if (!newSize.equals(oldSize)) {
+                
+                // store the new size
+                this.size = newSize;
+    
+                //notify layers of mapresize
+                for(var i=0, len=this.layers.length; i<len; i++) {
+                    this.layers[i].onMapResize();                
+                }
+    
+                var center = this.getCenter();
+    
+                if (this.baseLayer != null && center != null) {
+                    var zoom = this.getZoom();
+                    this.zoom = null;
+                    this.setCenter(center, zoom);
+                }
+    
             }
-
         }
     },
     
diff --git a/tests/Map.html b/tests/Map.html
index 16b954dda1..702ed21d78 100644
--- a/tests/Map.html
+++ b/tests/Map.html
@@ -1360,10 +1360,31 @@
         map.updateSize();
         t.eq(moveToCnt, 1, "updateSize move the map if it has a center");
     }
+    
+    function test_invisible_map(t) {
+        /** 
+         * This test confirms that initializing a map using an element that is 
+         * not currently displayed doesn't cause any trouble.
+         */
+        t.plan(1);
+        
+        var map, msg = "initializing a map on an undisplayed element";
+        try {
+            map = new OpenLayers.Map("invisimap");
+        } catch (err) {
+            msg += ": " + err;
+        }
+        t.ok(!!map, msg);
+        
+        if (map) {
+            map.destroy();
+        }        
+    }
 
   </script>
 </head>
 <body>
     <div id="map" style="width: 600px; height: 300px;"/>
+    <div style="display: none;"><div id="invisimap"></div></div>
 </body>
 </html>
