<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<script src="https://use.fontawesome.com/45e03a14ce.js"></script>
<div class="main_section">
<div class="container">
<div class="chat_container">
<div class="col-sm-3 chat_sidebar">
<div class="row">
<div id="custom-search-input">
<div class="input-group col-md-12">
<input type="text" class=" search-query form-control" placeholder="Conversation" />
<button class="btn btn-danger" type="button">
<span class=" glyphicon glyphicon-search"></span>
</button>
</div>
</div>
<div class="dropdown all_conversation">
<button class="dropdown-toggle" type="button" id="dropdownMenu2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<i class="fa fa-weixin" aria-hidden="true"></i>
All Conversations
<span class="caret pull-right"></span>
</button>
<ul class="dropdown-menu" aria-labelledby="dropdownMenu2">
<li><a href="#"> All Conversation </a> <ul class="sub_menu_ list-unstyled">
<li><a href="#"> All Conversation </a> </li>
<li><a href="#">Another action</a></li>
<li><a href="#">Something else here</a></li>
<li><a href="#">Separated link</a></li>
</ul>
