When creating a new Activity record, I need to require the "With contact" and "Assigned to" fields have a contact selected.
In the activity/form/activity.php file I can add 'required'=>TRUE to the various arrays, but that setting only works for the fields without a selector (e.g. subject, location, duration).
This can certainly be done with javascript in an extra.tpl file (and might be preferable, as it can be conditional to the activity type), but is there a way to modify either the template or php files to require a selected contact?