Bootstrap Glyph Icon Textfield - css

Question

I want to add a Textfield input-group-addon. The problem is that when I use this class with a glyphicon the icon is not positioned right next to textfield see the image below.
Maybe someone has some hints for me - why is that?
<!-- Text input-->
<div class="form-group">
<label class="col-md-4 control-label" for="name2"></label>
<div class="col-md-4">
<input id="name2" name="name2" type="text" placeholder="" class="form-control input-md">
</div>
</div>
<!-- Multiple Radios (inline) -->
<div class="form-group">
<label class="col-md-4 control-label" for="gender">Geschlecht</label>
<div class="col-md-4">
<label class="radio-inline" for="gender-0">
<input type="radio" name="gender" id="gender-0" value="1" checked="checked">
männlich
</label>
<label class="radio-inline" for="gender-1">
<input type="radio" name="gender" id="gender-1" value="2">
weiblich
</label>
</div>
</div>
<div class="form-group">
<label class="col-md-4 control-label" for="gender">Geburtsdatum</label>
<div class="col-md-4">
<div class='input-group date' id='datetimepicker2'>
<input type='text' class="form-control" />
<span class="input-group-addon">
<span class="glyphicon glyphicon-calendar"></span>
</span>
</div>
<script type="text/javascript">
$(function () {
$('#datetimepicker2').datetimepicker({
language: 'de'
});
});
</script>
</div>
</div>

Answer 1

Your code works fine with Bootstrap only (see this fiddle http://jsfiddle.net/WNAB8/1/)
The problem is in your own css. Use developer tools (F12) to find out what gives margin-right for the input or margin-left for the addon. Or optionally paste in your custom css so we can help you.
Update:
It definitely is because of given max-width for inputs. If for some reason you want to use max-width anyway, one solution is to give the max-width to .input-group:
.input-group {
max-width: 280px;
}
Demo: http://jsfiddle.net/WNAB8/5/

Answer 2

In your fiddle you are overriding bootstrap's textarea maxwidth option. Remove this from CSS:
/* Set width on the form input elements since they're 100% wide by default */
input,
select,
textarea {
max-width: 280px;
}
Working example
If you want to change the width of your text areas, change it using the form layout. From your layout you should look at the horizontal form and width can be changed by placing the input into a div controlled with the col-*:
<div class="col-sm-10">
<input type="email" class="form-control" id="inputEmail3" placeholder="Email">
</div>