tyb-code12.5.html

<div class="btn-group dropup">
  <button class="btn btn-default dropdown-toggle" data-toggle="dropdown">
    Choose One... 
    <span class="caret"></span>
  </button>
  <ul class="dropdown-menu">
    <li class="dropdown-header">Section 1</li>
    <li><a href="#">Item 1</a></li>
    <li><a href="#">Item 2</a></li>
    <li class="disabled"><a href="#">Item 3</a></li>
    <li class="divider"></li>
    <li class="dropdown-header">Section 2</li>
    <li><a href="#">Item 4</a></li>
    <li><a href="#">Item 5</a></li>
  </ul>
</div>