According to {T8106}, 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).
{F1020627}
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.
{F1020628}
And those i select are included in the input field
{F1020629}
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_
**Phabricator Version:** ef820ed1ee291307b3f61d77c65042bffe960cb9