diff --git a/common/content/util.js b/common/content/util.js
index a328ae20..6f8857be 100644
--- a/common/content/util.js
+++ b/common/content/util.js
@@ -417,11 +417,12 @@ const Util = Module("util", {
             null
         );
 
-        result.__iterator__ = asIterator
+        return {
+                __proto__: result,
+                __iterator__: asIterator
                             ? function () { let elem; while ((elem = this.iterateNext())) yield elem; }
-                            : function () { for (let i = 0; i < this.snapshotLength; i++) yield this.snapshotItem(i); };
-
-        return result;
+                            : function () { for (let i = 0; i < this.snapshotLength; i++) yield this.snapshotItem(i); }
+        }
     },
 
     /**