Need help keeping active Bootstrap dropdown menu highlighted

Hi all, I've just started using VWD2013 and am playing with the default Bootstrap template. My problem is that while I can use the @ActiveItem helper to highlight top-level menu items once they've been selected, this doesn't work for dropdown menus - for obvious reasons as soon as you select a dropdown menu item the top-level highlighting is lost. So for example:
<div class="navbar-collapse collapse"> <ul class="nav navbar-nav"> <li class="@ActiveItem("Index", "Home", null)">@Html.ActionLink("About", "Index", "Home")</li> <li class="@ActiveItem("About", "Home", null)">@Html.ActionLink("Services", "About", "Home")</li> <li class="@ActiveItem("Contact", "Home", null)" ...