The autocompletes used in the competency report have been bastardised to
redirect on selection. Unfortunately this also applies when when making
null-op changes like deleting the initial "Please select a value"
option.
The autocomplete code removes all current options before creating an
option, and because of this redirect the browser is redirecting before
the new value can be entered, but we retain a reference to the field as
`$this->field`, which is now stale.
Andrew Nicols
dff4bc87f5