--- a/web/captcha.py	Mon Apr 12 14:41:01 2010 +0200
+++ b/web/captcha.py	Tue Apr 13 12:19:24 2010 +0200
@@ -70,8 +70,7 @@
         return img + super(CaptchaWidget, self).render(form, field, renderer)
 
     def process_field_data(self, form, field):
-        captcha = form._cw.get_session_data(field.input_name(form), None,
-                                            pop=True)
+        captcha = form._cw.session.data.pop(field.input_name(form), None)
         val = super(CaptchaWidget, self).process_field_data(form, field)
         if val is None:
             return val # required will be checked by field