bootstrap multiselect style error

Question

I have a styling problem with a bootstrap form component. The component is:

<div class="form-group">
  <div class="col-xs-12">
    <select multiple class="chosen-select">
      <option>option 1</option>
      <option>option 2</option>
    </select>
  </div>
</div>

For some reason though, the col-xs-12 is not styling the multiselect responsively. For all my other normal components, the bootstrap grid layout works well with window resizing, and the multiselect works great when refreshing a page. When I resize, however, the multiselect grid screws up. Also, there is a bit of a spacing problem between each multiselect and the form element underneath that multiselect. You can see in the pictures:

any ideas? Thanks