diff --git a/common/content/bookmarks.js b/common/content/bookmarks.js
index 657e9c06..fdfcbfb0 100644
--- a/common/content/bookmarks.js
+++ b/common/content/bookmarks.js
@@ -82,6 +82,7 @@ function Bookmarks() //{{{
     function Cache(name, store, serial)
     {
         const rootFolders = [bookmarksService.toolbarFolder, bookmarksService.bookmarksMenuFolder, bookmarksService.unfiledBookmarksFolder];
+        const sleep = liberator.sleep;
 
         let bookmarks = [];
         let self = this;
@@ -141,7 +142,7 @@ function Bookmarks() //{{{
             if (loading)
             {
                 while (loading)
-                    liberator.sleep(10);
+                    sleep(10);
                 return bookmarks;
             }