<p dir="auto">In Bootstrap 3.2.0 it is at the moment possible to have more accordion items at once open. But normally only entry should be open.</p>
<p dir="auto">How i made this:</p>
<ol dir="auto">
<li>Normal Click on accordion item "<code class="notranslate">Collapsible Group Item #3</code>"</li>
<li>Fast Click on accordion item "<code class="notranslate">Collapsible Group Item #2</code>"</li>
<li>Fast Click on accordion item "<code class="notranslate">Collapsible Group Item #1</code>" (as soon as possible after step 2))</li>
</ol>
<p dir="auto">Result (Image below -&gt; two open accordion items):<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/5426291/4476585/50a8b87a-4977-11e4-95f5-0427e3048db5.jpg"><img src="https://cloud.githubusercontent.com/assets/5426291/4476585/50a8b87a-4977-11e4-95f5-0427e3048db5.jpg" alt="accordion" style="max-width: 100%;"></a></p>
<p dir="auto">Step 1. Navigate to this page: <a href="http://getbootstrap.com/javascript/#collapse" rel="nofollow">http://getbootstrap.com/javascript/#collapse</a><br>
Step 2. Click on one of the links that trigger opening of the accordion sections (ie. Collapsible Group Item <code class="notranslate">#1</code>)<br>
Step 3. Before the section's opening animation has a chance to complete (the one from 'Step 2' above) click on a different link to trigger opening a second panel (ie. Collapsible Group Item <code class="notranslate">#2</code>)</p>
<p dir="auto">At this point you should see that you have two accordion panels open at the same time.</p>