The following code shows how to create icon button dropdown.
<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'
src='http://code.jquery.com/jquery-1.10.1.js'></script>
<script type='text/javascript'
src="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/js/bootstrap.min.js"></script>
<link rel="stylesheet" type="text/css"
href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css">
<style type='text/css'>
.navbar-fixed-top .btn-group-merge {
margin-left: -5px;
}<!--from w ww. ja v a 2 s. c om-->
.navbar-fixed-top .btn-group-merge:first-child {
margin-left: 0;
}
.navbar-fixed-top .btn-group-merge .btn {
border-radius: 0 4px 4px 0;
}
.navbar-fixed-top .btn-group-merge:first-child .btn {
border-radius: 4px 0 0 4px;
}
</style>
</head>
<body>
<div class="navbar navbar-fixed-top">
<div class="navbar-inner">
<div class="container">
<div class="pull-left">
<div class="btn-group btn-group-merge">
<a class="btn" href="#" data-toggle="dropdown">
<i class="icon icon-certificate"></i></a>
<ul class="dropdown-menu">
<li><a href="#">One</a></li>
<li><a href="#">Two</a></li>
<li><a href="#">Three</a></li>
</ul>
</div>
<div class="btn-group btn-group-merge">
<a class="btn" href="#" data-toggle="dropdown">
<i class="icon icon-comment"></i></a>
<ul class="dropdown-menu">
<li><a href="#">A</a></li>
<li><a href="#">B</a></li>
<li><a href="#">C</a></li>
</ul>
</div>
</div>
</div>
</div>
</div>
</body>
</html>