Expanded the fix in [12663] to cover CSS declarations, which were also affected by the bug. Refs #12879.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12665 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 3 insertions, 1 deletions

diff --git a/django/forms/widgets.py b/django/forms/widgets.py
index 482c718118..81db2a24f3 100644
--- a/django/forms/widgets.py
+++ b/django/forms/widgets.py
@@ -82,7 +82,9 @@ class Media(StrAndUnicode):
     def add_css(self, data):
         if data:
             for medium, paths in data.items():
-                self._css.setdefault(medium, []).extend([path for path in paths if path not in self._css[medium]])
+                for path in paths:
+                    if not self._css.get(medium) or path not in self._css[medium]:
+                        self._css.setdefault(medium, []).append(path)
 
     def __add__(self, other):
         combined = Media()