title: NgbDropdown: remove dropdown arrow
body: <p>I'm using the <code>NgbDropdown</code> component in my Angular 2 application. It is working fine, however I want to remove the arrow that is displayed on the right side of the button.</p>
  
  <pre><code>&lt;div class="d-inline-block" ngbDropdown #myDrop="ngbDropdown"&gt;
    &lt;button class="btn btn-outline-primary" id="dropdownMenu1" ngbDropdownToggle&gt;Toggle dropdown&lt;/button&gt;
    &lt;div class="dropdown-menu" aria-labelledby="dropdownMenu1"&gt;
      &lt;button class="dropdown-item"&gt;Action - 1&lt;/button&gt;
      &lt;button class="dropdown-item"&gt;Another Action&lt;/button&gt;
      &lt;button class="dropdown-item"&gt;Something else is here&lt;/button&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/7qfof.png" rel="noreferrer">Dropdown Image</a></p>