diff --git a/filer/admin/folderadmin.py b/filer/admin/folderadmin.py
index <HASH>..<HASH> 100644
--- a/filer/admin/folderadmin.py
+++ b/filer/admin/folderadmin.py
@@ -44,6 +44,7 @@ from filer.utils.filer_easy_thumbnails import FilerActionThumbnailer
 from filer.thumbnail_processors import normalize_subject_location
 from django.conf import settings as django_settings
 import os
+import re
 import itertools
 
 
@@ -288,8 +289,9 @@ class FolderAdmin(PrimitivePermissionAwareModelAdmin):
         if order_by is not None:
             order_by = order_by.split(',')
             order_by = [field for field in order_by
-                        if field.replace('-', '') in self.order_by_file_fields]
-            file_qs = file_qs.order_by(*order_by)
+                        if re.sub(r'^-', '', field) in self.order_by_file_fields]
+            if len(order_by) > 0:
+                file_qs = file_qs.order_by(*order_by)
 
         folder_children = []
         folder_files = []
@@ -319,7 +321,7 @@ class FolderAdmin(PrimitivePermissionAwareModelAdmin):
         except:
             permissions = {}
 
-        if order_by is None:
+        if order_by is None or len(order_by) == 0:
             folder_files.sort()
         
         items = folder_children + folder_files
Check if order_by field is in whitelist with regexp