[imp] Autocomplete auto-select when composing?

[Michael Wing]

When composing a message, after typing a few characters into the "To"
field, the autocomplete brings up a dropdown list of matching addresses.
 Is there any way to make it so that the address is actually populated IN
the To field?  For instance, if there is only one matching address,
currently I still have to hit Tab, or the down-arrow to select that
address.  Ideally, that one single address would be automatically populated
in the To field.  Other desktop mail clients like Outlook behave this way.
 Can anyone tell me if this behavior is available, or guide me to where I
might make the desired change?

Thanks!

Michael