hide -> hide (open)

--- a/src/HOL/Fun.thy	Thu Jun 12 23:12:54 2008 +0200
+++ b/src/HOL/Fun.thy	Fri Jun 13 15:22:07 2008 +0200
@@ -482,7 +482,7 @@
 lemma bij_swap_iff: "bij (swap a b f) = bij f"
 by (simp add: bij_def)
 
-hide const swap
+hide (open) const swap
 
 subsection {* Proof tool setup *}