diff --git a/lib/OpenLayers/BaseTypes/Class.js b/lib/OpenLayers/BaseTypes/Class.js
index 1e242f55bb..6f64d3f961 100644
--- a/lib/OpenLayers/BaseTypes/Class.js
+++ b/lib/OpenLayers/BaseTypes/Class.js
@@ -91,7 +91,7 @@ OpenLayers.Util.extend = function(destination, source) {
     destination = destination || {};
     if (source) {
         for (var property in source) {
-            if (source.hasOwnProperty(property)) {
+            if (Object.prototype.hasOwnProperty.call(source, property)) {
                 var value = source[property];
                 if (value !== undefined) {
                     destination[property] = value;
diff --git a/tests/Util.html b/tests/Util.html
index 43db83c06d..e137d0f7ce 100644
--- a/tests/Util.html
+++ b/tests/Util.html
@@ -1120,10 +1120,34 @@
         t.eq(OpenLayers.Util.getFormattedLonLat(-181, "lon"), "179°00'00\"E", "crossing dateline from the west results in correct east coordinate");
         t.eq(OpenLayers.Util.getFormattedLonLat(181, "lon"), "179°00'00\"W", "crossing dateline from the east results in correct west coordinate");
     }
-    
   </script>
 </head>
 <body>
     <div id="map" style="width: 1024px; height: 512px;"/>
+    <script>
+    /**
+     * To test that we can safely call OpenLayers.Util.extend with an Event
+     * instance, we need to capture a real event.
+     */
+    var loadEvent;
+    window.onload = function(evt) {
+        loadEvent = evt || window.event;
+    }
+    function test_extend_event(t) {
+        t.plan(2);
+        t.ok(loadEvent, "loadEvent recorded");
+        var extended, err;
+        try {
+            extended = OpenLayers.Util.extend({foo: "bar"}, loadEvent);
+        } catch (e) {
+            err = e;
+        }
+        if (err) {
+            t.fail("Failed to extend event");
+        } else {
+            t.eq(extended && extended.foo, "bar", "extended with event");
+        }
+    }
+    </script>
 </body>
 </html>
