Index: django/contrib/admin/widgets.py
===================================================================
--- django/contrib/admin/widgets.py	(revision 9845)
+++ django/contrib/admin/widgets.py	(working copy)
@@ -174,7 +174,7 @@
     def value_from_datadict(self, data, files, name):
         value = data.get(name, None)
         if value and ',' in value:
-            return data[name].split(',')
+            return filter(None, [v.strip() for v in data[name].split(',')])
         if value:
             return [value]
         return None