title: Form group margin bottom removed
body: <p>I am creating a nested row with some <code>form-group</code> element in a bootstrap tab panel.
  Unfortunately those form-groups are not vertically spaced correctly despite to the fact that <code>form-group</code> has a <code>margin-bottom</code> of <code>15px</code> in <code>bootstrap.css</code>.
  Can anybody suggest why and a solution?</p>
  
  <p>Please have a look at the following <a href="http://www.bootply.com/HAEZwoVo67" rel="noreferrer">fiddle</a> to understand.</p>
  
  <p>Thanks</p>