ASPNET MVC5 website, Visual Studio 2015
There's really nothing special in following dropdown:

<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Admin</a>
<ul class="dropdown-menu">
<li><a href="/Categories">Manage Categories</a></li>
<li><a href="/RolesAdmin">Manage Roles</a></li>
<li><a href="/UsersAdmin">Manage Users</a></li>
<li role="separator" class="divider"></li>
<li><a href="/Gifts/PendingApproval">Pending approval</a></li>
</ul>
</li>

and it's working as expected until a "right-to-left" culture is chosen, firing related .js and .css to load, after having installed Twitter Bootstrap RTL v. 3.0 package:

bundles.Add(new ScriptBundle("~/bundles/bootstrap-rtl").Include(
"~/Scripts/bootstrap-rtl.js",
"~/Scripts/respond.js"));

bundles.Add(new StyleBundle("~/Content/css-rtl").Include(
"~/Content/bootstrap-rtl.css",
"~/Content/site.css"));

Choosing such a language (Arabic for instance), RTL versions are loaded

@Styles.Render("~/Content/css" + (CultureHelper.IsRighToLeft() ? "-rtl" : ""))
@Scripts.Render("~/bundles/bootstrap" + (CultureHelper.IsRighToLeft() ? "-rtl" : ""))

somewhat interfering with any dropdown, preventing them from working (i.e. clicking on "Admin" nothing happens). Changing back to any LTR language makes dropdowns work again.