According to T8106: Allow a task to be assigned to multiple people, a task must always be assigned to only 0 or 1 person.

When creating (or editing) a task, in the Assigned to field i may write the name of an user. After i select the desired user to assign from the dropdown, the input is still a input text but won't allow me to write any more names (as expected).

If at this moment i click the search icon (magnifier) of the input, it will show me a list of all the contributors; i am allowed to _select_ as many as i want.

And those i select are included in the input field

But when i save the task, only the first user in the input is saved as the task owner, albeit no warning is issued at any time.

Expected: Since i can not add more than one owner, the select button of the user list be _disabled_

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