callback when user selects row from Autocomplete mixin

The autocomplete mixin provides no callback mechanism to know when the user selects an item from the list. I found this thread, but no corresponding JIRA ticket (did search but this is my first time here): http://osdir.com/ml/users-tapestry-apache/2010-05/msg00306.html
Having a callback would greatly enhance this mixin as it would allow for an easy response to a user selection.