diff --git a/browser/base/content/tabview/modules/utils.jsm b/browser/base/content/tabview/modules/utils.jsm
index ab915f12cf76..40896b6c6e0b 100644
--- a/browser/base/content/tabview/modules/utils.jsm
+++ b/browser/base/content/tabview/modules/utils.jsm
@@ -576,7 +576,7 @@ let Utils = {
   // Function: isDOMElement
   // Returns true if the given object is a DOM element.
   isDOMElement: function(object) {
-    return (object && typeof(object.nodeType) != 'undefined' ? true : false);
+    return object instanceof Ci.nsIDOMElement;
   },
 
   // ----------