diff --git a/Text/Formlets.hs b/Text/Formlets.hs
--- a/Text/Formlets.hs
+++ b/Text/Formlets.hs
@@ -4,6 +4,7 @@
                      , runFormState 
                      , massInput
                      , xml, plug
+                     , withPrefix
                      , Env , Form , Plus (..)
                      , File (..), ContentType (..), FormContentType (..)
                      )
@@ -172,7 +173,7 @@
        nullToMaybe x  = Just x
 
 withPrefix :: String -> Form xml m a -> Form xml m a
-withPrefix prefix (Form f) = Form $ \env -> (changePrefix prefix >> f env)
+withPrefix prefix (Form f) = Form $ \env -> (modify (const (0, prefix)) >> f env)
 
 -----------------------------------------------
 -- Private methods
diff --git a/formlets.cabal b/formlets.cabal
--- a/formlets.cabal
+++ b/formlets.cabal
@@ -1,5 +1,5 @@
 Name:            formlets
-Version:         0.4.6
+Version:         0.4.7
 Synopsis:        Formlets implemented in Haskell
 Description:     A modular way to build forms based on applicative functors, as
                  described in: