diff --git a/sugar/activity/bundlebuilder.py b/sugar/activity/bundlebuilder.py
index 16e47f78..8e8c49d6 100644
--- a/sugar/activity/bundlebuilder.py
+++ b/sugar/activity/bundlebuilder.py
@@ -54,22 +54,18 @@ class _DefaultFileList(list):
         if os.path.isfile(_get_source_path('NEWS')):
             self.append('NEWS')
 
-class _ManifestFileList(list):
+class _ManifestFileList(_DefaultFileList):
     def __init__(self, manifest):
+        _DefaultFileList.__init__(self)
         self.append(manifest)
 
         f = open(manifest,'r')
         for line in f.readlines():
             stripped_line = line.strip()
-            if stripped_line:
+            if stripped_line and not stripped_line in self:
                 self.append(stripped_line)
         f.close()
 
-        defaults = _DefaultFileList()
-        for path in defaults:
-            if not path in self:
-                self.append(path)
-
 def _extract_bundle(source_file, dest_dir):
         if not os.path.exists(dest_dir):
             os.mkdir(dest_dir)