Bootstrap horizontal form has additional margins - css

Question

The button that's next to a column containing a select element appears to have some extra margins on it. On my actual site it seems to be extra positive margin, while on CodePen it appears to be negative.
I suspect they are the same problem though with the markup though. Here's the CodePen demo: http://codepen.io/anon/pen/gabZMo?editors=100
<div class="row">
<div class="form-horizontal col-md-6">
<div class="form-group">
<div class="col-sm-8">
<select class="form-control">...</select>
</div>
<button class="btn btn-default col-sm-4">New Event</button>
</div>
<button class="btn btn-primary btn-block">Free Quote</button>
</div>
</div>
I've looked through the Bootstrap docs and this should be the correct markup. I've also tried wrapping the button in its own column, but that didn't change anything.

Answer 1

You have 3 options to resolve the problem,
Put the <button class="btn btn-primary btn-block">Free Quote</button> inside <div class="form-group"></div>
Reason the button is pushing left of right because col-sm-4 selector has left and right padding 15px which is getting overwritten by btn-default selector padding: 6px 12px;
So add custom selector custom-margin and define custom CSS
1 HTML
<div class="row">
<div class="form-horizontal col-md-6">
<div class="form-group">
<div class="col-sm-8">
<select class="form-control">...</select>
</div>
<button class="btn btn-default col-sm-4 custom-margin">New Event</button>
</div>
<div class="form-group">
<button class="btn btn-primary btn-block">Free Quote</button>
</div>
</div>
</div>
Fiddle 1
2 HTML
<div class="row">
<div class="form-horizontal col-md-6">
<div class="form-group">
<div class="col-sm-8">
<select class="form-control">...</select>
</div>
<button class="btn btn-default col-sm-4 custom-margin">New Event</button>
<button class="btn btn-primary btn-block">Free Quote</button>
</div>
</div>
</div>
Fiddle 2
Or Do it right way
3 HTML
<div class="row">
<div class="col-sm-6">
<div class="row">
<div class="col-sm-8">
<div class="form-group">
<select class="form-control">...</select>
</div>
</div>
<div class="col-sm-4">
<div class="form-group">
<button class="btn btn-default btn-block">New Event</button>
</div>
</div>
<div class="col-sm-12">
<div class="form-group">
<button class="btn btn-primary btn-block">Free Quote</button>
</div>
</div>
</div>
</div>
</div>
</div>
Fiddle 3

Answer 2

You don't want to use col-sm-4 directly on the button. Put btn-block on the button and stick it in a col-sm-4 div, like so:
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" />
<div class="row">
<div class="form-horizontal col-md-6">
<div class="form-group">
<div class="col-xs-8">
<select class="form-control">
<option value="1">Test Event</option>
<option value="7">Test Event 2: The Re-testening</option>
</select>
</div>
<div class="col-xs-4">
<button class="btn btn-default btn-block">New Event</button>
</div>
</div>
<button class="btn btn-primary btn-block">Free Quote</button>
</div>
</div>