Angular strap empty dropdown

HTML

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.9/angular.min.js"></script>
<link rel="stylesheet" href="https://cdn.rawgit.com/twbs/bootstrap/master/dist/css/bootstrap.css">
<link rel="stylesheet" href="https://cdn.rawgit.com/mgcrea/angular-motion/master/dist/angular-motion.css">
<script src="https://cdn.rawgit.com/jonanderdev/angular-strap/master/dist/angular-strap.min.js"></script>
<script src="https://cdn.rawgit.com/mgcrea/angular-strap/master/dist/angular-strap.tpl.min.js"></script>
<div id="sandbox" ng-controller="bpDemoCtrl">
    <button type="button" 
    ng-model="country" 
    bs-select="" 
    bs-options="country.key as country.label for country in countries" 
    class="btn button-select button-select-with-label caret-thin form-control"></button>
</div>

CSS

.select.dropdown-menu {
  animation: none !important;
  //overflow: initial;
  //max-height: none;
  overflow: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  max-height: 250px;
  margin-bottom: 25px;
  opacity: 1;
  margin-top: -4px;
  min-width: 0 !important;
  max-width: 100%;
  border-top-left-radius: 0;
  border-top: 0 !important;
  border-top-right-radius: 0;
  border-bottom-left-radius: 4px;
  border-bottom-right-radius: 4px;
  transition: none;
  padding-bottom: 0 !important;
  border-color: #c8cbcc !important;}

JavaScript

'use strict';

var app = angular.module('myApp', ['mgcrea.ngStrap']);



app.controller('bpDemoCtrl', function($scope) {
    $scope.countries = [
    { "label": "Afghanistan", "key": "AF"} ,
    { "label": "Ă…land Islands", "key": "AX"} ,
    { "label": "Albania", "key": "AL"} ,
    { "label": "Algeria", "key": "DZ"} ,
    { "label": "American Samoa", "key": "AS"} ,
    { "label": "AndorrA", "key": "AD"} ,
    { "label": "Angola", "key": "AO"} ,
    { "label": "Anguilla", "key": "AI"} ,
    { "label": "Antarctica", "key": "AQ"} ,
    { "label": "Antigua and Barbuda", "key": "AG"} ,
    { "label": "Argentina", "key": "AR"} ,
    { "label": "Armenia", "key": "AM"} ,
    { "label": "Aruba", "key": "AW"} ,
    { "label": "Australia", "key": "AU"} ,
    { "label": "Austria", "key": "AT"} ,
    { "label": "Azerbaijan", "key": "AZ"} ,
    { "label": "Bahamas", "key": "BS"} ,
    { "label": "Bahrain", "key": "BH"} ,
    { "label": "Bangladesh", "key": "BD"} ,
    { "label": "Barbados", "key": "BB"} ,
    { "label": "Belarus", "key": "BY"} ,
    { "label": "Belgium", "key": "BE"} ,
    { "label": "Belize", "key": "BZ"} ,
    { "label": "Benin", "key": "BJ"} ,
    { "label": "Bermuda", "key": "BM"} ,
    { "label": "Bhutan", "key": "BT"} ,
    { "label": "Bolivia", "key": "BO"} ,
    { "label": "Bosnia and Herzegovina", "key": "BA"} ,
    { "label": "Botswana", "key": "BW"} ,
    { "label": "Bouvet Island", "key": "BV"} ,
    { "label": "Brazil", "key": "BR"} ,
    { "label": "British Indian Ocean Territory", "key": "IO"} ,
    { "label": "Brunei Darussalam", "key": "BN"} ,
    { "label": "Bulgaria", "key": "BG"} ,
    { "label": "Burkina Faso", "key": "BF"} ,
    { "label": "Burundi", "key": "BI"} ,
    { "label": "Cambodia", "key": "KH"} ,
    { "label": "Cameroon", "key": "CM"} ,
    { "label": "Canada", "key": "CA"} ,
    { "label": "Cape Verde", "key": "CV"} ,
    { "label": "Cayman Islands", "key": "KY"} ,
    { "label": "Central African Republic", "key": "CF"} ,
   ...