How to change bootstrap select arrows to glyphicon?

I want to achieve something like this, except arrow should be bootstrap glyphicon icon:

I really don't know how to make this using bootstrap. I was trying to do this like this:

<div class="my-select">
  <div class="select-side">
    <i class="glyphicon glyphicon-menu-down"></i>
  </div>
  <select class="form-control" id="sel1">
    <option>1</option>
    <option>2</option>
    <option>3</option>
  </select>
</div>

by setting up select-side as absolute on my-select and manipulate it, but no matter how hard i try, i can't fit this blue div with border under whole select. AND when you click on that arrow- it doesn't work.

Only problem I have right now is that clicking on select-side div won't open panel.

EDIT2: Problem Solved, WORKING DEMO:

http://codepen.io/Deathgazeroo/pen/wWWMqJ