title: Buttons not joining in Bootstrap Button Groups
body: <p><img src="https://i.stack.imgur.com/9ojuq.png" alt="enter image description here">
  This is very bizarre and must be something silly. This works fine... </p>
  
  <pre><code>&lt;div class="btn-group" role="group" id="lead_buttons"&gt;
                    &lt;a type="button" class="btn btn-default lead" id="lead_0"&gt;All&lt;/a&gt;
                    &lt;a type="button" class="btn btn-default lead" id="lead_1"&gt;Lead&lt;/a&gt;
                  &lt;/div&gt; 
  </code></pre>
  
  <p>... but when I change class="btn-group" to class="btn-group-sm" the buttons aren't joined anymore. They are separate. </p>