diff --git a/source/js/OxUI.js b/source/js/OxUI.js
index 3cf30cc7..0a5c8a2b 100644
--- a/source/js/OxUI.js
+++ b/source/js/OxUI.js
@@ -374,7 +374,7 @@ Provides function Ox.UI([options], callback) that fires when
         }
 
         Ox.UI.ready = function(callback) {
-            if (!documentReady) {
+            if (!Ox.UI.$window) {
                 documentReadyCallbacks.push(callback);
             } else {
                 callback();