JscrollPane Demo

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>
<script src="https://www.elala.in/finaldemo/js/bootstrap-select.js"></script>
<script src="https://www.elala.in/finaldemo/js/jquery.jscrollpane.min.js"></script>
<script src="https://www.elala.in/finaldemo/js/jquery.mousewheel.js"></script>
<link rel="stylesheet" href="https://www.elala.in/finaldemo/css/bootstrap-select.css">
<link rel="stylesheet" href="https://www.elala.in/finaldemo/css/jquery.jscrollpane.css">
<body>
<select id="country" name="country" class="form-control selectpicker" title="test">
          <option value="1">Argentina1</option>
          <option value="2">Argentina2</option>
          <option value="3">Argentina3</option>
		  <option value="4">Argentina4</option>
		  <option value="5">Argentina5</option>
		  <option value="6">Argentina6</option>
		  <option value="7">Argentina7</option>
		  <option value="8">Argentina8</option>
		  <option value="9">Argentina9</option>
		  <option value="10">Argentina10</option>
		  <option value="11">Argentina11</option>
</select>
</body>

CSS

@import url('http://dropdown-test.iprojectlab.com/css/bootstrap-select.css');
@import url('http://dropdown-test.iprojectlab.com/css/bootstrap-select.css');

body {
      padding-top: 70px;
    }
	.bootstrap-select { width:50% !important; margin:0 25px !important; }

JavaScript

$(document).ready(function () {
    $(document).delegate(".dropdown-toggle","click",function(){
		var jDropdown = $(this).siblings(".dropdown-menu").find("ul.dropdown-menu");
		jDropdown.jScrollPane();
	});
	$(document).delegate(".selectpicker","change",function(){
		$(this).find("option:selected").remove();
		$(this).selectpicker("refresh");
	});
});