I use bootstrap select option field with class `form-control` 

Here is my code: 

```
<select class="form-control" onchange="location = this.value;">
            <option>Select a Generic Name</option>
            <option value="1">Title 1</option>
            <option value="2">Title 2</option>
 </select>

```

But in dropdown option down arrow icon not displaying

[![See Image](https://i.stack.imgur.com/LT0Jg.jpg)](https://i.stack.imgur.com/LT0Jg.jpg)

CSS: 

```
.form-control {
display: block;
width: 100%;
height: 34px;
padding: 6px 12px;
font-size: 14px;
line-height: 1.42857143;
color: #555;
background-color: #fff;
background-image: none;
border: 1px solid #ccc;
border-radius: 4px;
-webkit-box-shadow: inset 0 1px 1px rgba(0,0,0,.075);
box-shadow: inset 0 1px 1px rgba(0,0,0,.075);
-webkit-transition: border-color ease-in-out .15s,-webkit-box-shadow ease-in-out .15s;
-o-transition: border-color ease-in-out .15s,box-shadow ease-in-out .15s;
transition: border-color ease-in-out .15s,box-shadow ease-in-out .15s;}

```

What is the main problem to displaying this icon?