title: Bootstrap v4 'hidden-xs-up' not working
body: <p>I have the following code in a view:</p>
  
  <pre><code>&lt;button type="button" tabindex="500" title="Abort ongoing upload" class="btn btn-secondary hidden-xs-up"&gt;
      &lt;i class="fa fa-ban"&gt;&lt;/i&gt;  
      &lt;span class="hidden-xs-up"&gt;Cancel&lt;/span&gt;
  &lt;/button&gt;
  </code></pre>
  
  <p>I am using Bootstrap v4, whose documentation mentions that 'hidden-xs-up' (which has replaced the erstwhile 'hidden-xs') will hide the particular element from devices which are 'xs' &amp; upwards. Sadly, this doesn't seem to happen in my case and the button appears. Infact, there are some other elements too with the class, but they appear too.</p>
  
  <p>In the Chrome debugger window, there are no styles associated with the class. Why is this happening and what is the solution to it?</p>