steps to reproduce:
- click on send page by e-mail
- start typing the name of an user
- auto-complete will kick in-
- do not write the entire user name and press return key
- you will see that the value in the filed won't be the full auto-complete suggestion, instead, it is only what you have typed.
This generates an error like: "The message could not be sent to sori: unknown email address."
User "sori" does not exist, autocomplete should have put "XWiki.Sorinello" instead.