Index: django/template/context.py
===================================================================
--- django/template/context.py	(revision 4542)
+++ django/template/context.py	(working copy)
@@ -60,7 +60,7 @@
 
     def update(self, other_dict):
         "Like dict.update(). Pushes an entire dictionary's keys and values onto the context."
-        self.dicts = [other_dict] + self.dicts
+        self.dicts[0].update(other_dict)
 
 # This is a function rather than module-level procedural code because we only
 # want it to execute if somebody uses RequestContext.