Bootstrap Dropdown
<ul class="dropdown-menu scrollable-menu" role="menu">
<li><a href="#">Action</a></li>
<li><a href="#">Another action</a></li>
<li><a href="#">Something else here</a></li>
<li><a href="#">Action</a></li>
..
<li><a href="#">Action</a></li>
<li><a href="#">Another action</a></li>
</ul>
Talented Tarsier