fab-manager/app/frontend/templates/admin/settings/select-multiple.html

<form class="{{classes}}" name="settingSelectMultipleForm">
    <div class="form-group">
        <label for="setting-{{setting.name}}" class="control-label m-r" translate>{{ label }}</label>
        <select class="form-control"
              id="setting-{{setting.name}}"
              ng-model="selection"
              ng-required="true"
              ng-options="opt for opt in options"
              multiple>
        </select>
    </div>
    <div>
        <button ng-click="removeItem()" class="btn btn-default"><i class="fa fa-trash"></i></button>
        <button ng-click="addItem()" class="btn btn-default"><i class="fa fa-plus"></i></button>
    </div>
  <button name="button" class="btn btn-warning m-t" ng-click="save(setting)" ng-disabled="settingSelectMultipleForm.$invalid" translate>{{ 'app.shared.buttons.save' }}</button>
</form>