diff --git a/app/assets/javascripts/app/lib/base/desktop-notify.js b/app/assets/javascripts/app/lib/base/desktop-notify.js
index e746531da..5e977b21d 100644
--- a/app/assets/javascripts/app/lib/base/desktop-notify.js
+++ b/app/assets/javascripts/app/lib/base/desktop-notify.js
@@ -142,9 +142,12 @@
         } else if (navigator.mozNotification) {
             //Firefox Mobile
             permission = PERMISSION_GRANTED;
-        } else if (win.external && win.external.msIsSiteMode()) { /* keep last */
+        } else if (win.Notification && win.Notification.permission) {
+            // Firefox 23+
+            permission = win.Notification.permission;
+        } else if (win.external && (win.external.msIsSiteMode() !== undefined)) { /* keep last */
             //IE9+
-            permission = PERMISSION_GRANTED;
+            permission = win.external.msIsSiteMode() ? PERMISSION_GRANTED : PERMISSION_DEFAULT;
         }
         return permission;
     }