title: select2 does not display correctly (Using cdn)
body: <p>I'm trying to complete my website with some java's plugin, I'm on Symfony 4 and I use the CDN bootstrap twitter. </p>
  
  <p>When I put the select2 plugin into the templates all is working properly, the select2 plugin does apply correctly.</p>
  
  <p>However I don't want to load select2 directly from the templates I want to run it from <code>app.js</code> but it didn't work properly, the select2 plugin is activated but it's weird, I'll show you the result below.</p>
  
  <p><a href="https://i.stack.imgur.com/8WWv1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8WWv1.png" alt=""></a></p>
  
  <p><strong>There is my app.js code:</strong> </p>
  
  <pre><code>let $ = require('jquery');
  
  require('../css/app.css');
  require('select2');
  
  $('select').select2();
  
  
  console.log('Hello Webpack Encore! Edit me in assets/js/app.js');
  </code></pre>
  
  <p>I'm sorry for my bad English, I'll thank you all for reading my post to the end!</p>