Auto populate contact in "to" field when composing msg

[ViziSites]

I am trying to figure out why the "to" field does not automatically populate with the contact from memory after I type the first character in the contact's email address.
Any help would be appreciated, thanks!

[JohnDoh]

What do you mean by "from memory"? Contacts from your Roundcube "personal address book" are used for auto complete by default, this can be changed from the Roundcube config file as well as by plugins.