The 'Owner'-Dropdown is not sorted by last-name anymore, but will add notified users at the top without any visible order.
We could leave the top-section of the list ensuring:
- The section of notified users is also sorted by last name
- The whole list of assignable Users is below the notified users, divided by a horizontal ruler (-----)
- All users will be shown, again if already notified, in the lower section of the dropdown.