[alpha 6] Alert with no margin make navbar display incorrecttly

Created by: vutaviva

I try display Alert with button on top page. My page has navbar on top. I modify Alert with no margin. As as result, navbar display with big margin on right.

<div class="alert alert-danger alert-dismissible fade show" role="alert" style="margin-bottom: 0">
     <button type="button" class="close" data-dismiss="alert" aria-label="Close">
               <span aria-hidden="true">&times;</span>
     </button>
      this for test
</div>
<nav class="navbar navbar-toggleable navbar-light">
...
</nav>