ui-select issue

controller.js

$scope.fetchSearchableUsers = function (query) {
           messageService.Contacts.get({name: query, allContacts: true, contactType: 'user'}, function(contacts){
                      $scope.searchableUsers = contacts.results;
           });
};

select.html

<ui-select multiple
           ng-model="threadFilters.subscribers"
           theme="select2"
           style="width: 100%;">

           <ui-select-match placeholder="Search Users..">{{ $item.name }}</ui-select-match>
           
           <ui-select-choices repeat="user in searchableUsers"
                           refresh="fetchSearchableUsers($select.search)"
                           refresh-delay="350">
                      {{ user.name }}
           </ui-select-choices>

</ui-select>