diff -r 541659c39f6a -r c8a5ac2d1eaa server/session.py
--- a/server/session.py	Sat Oct 09 00:05:50 2010 +0200
+++ b/server/session.py	Sat Oct 09 00:05:52 2010 +0200
@@ -46,6 +46,7 @@
 # anyway in the later case
 NO_UNDO_TYPES.add('is')
 NO_UNDO_TYPES.add('is_instance_of')
+NO_UNDO_TYPES.add('cw_source')
 # XXX rememberme,forgotpwd,apycot,vcsfile
 
 def _make_description(selected, args, solution):