Most likely it's because the user list is cached (or in the ViewState). I may have missed it, but I didn't see anywhere in the code where Vince flushed the cache or the ViewState (it's been a couple months since I looked at it though).

I know I experienced a similar issue, and wound up writing some code to clear the cache and/or ViewState.

Anyway, sorry for the vague answer - but I'd look at Cache and ViewState. You may need to write some code yourself to handle the issue.

Tim