I had a problem with a drop-down menu in bootstrap not working which was coded as:
<li class="dropdown btn-group-vertical">
<a href="../SEO.html" class="dropdown-toggle" data-toggle="dropdown">SEO <i class="fa fa-stack-4x fa-angle-down"></i></a>
<ul class="dropdown-menu bg-darkest-gray">
I replaced with:
<li class="dropdown btn-group-vertical">
<button class="dropdown-toggle" data-toggle="dropdown">SEO <i class="fa fa-stack-4x fa-angle-down"></i></button>
<ul class="dropdown-menu bg-darkest-gray">
And that seemed to solve the issue.