Showing a Plone tab as selected

I just added a "Podcasts" tab to ITauthor.com, but initially it wasn't displaying as selected. The <li> element should get class="selected" when it's selected, but it resolutely stayed class="plain" and so it didn't come to the front when clicked.

After a lot of digging I discovered the solution in:
http://plone.org/documentation/how-to/changing-tabs

The trick is that you have to make sure that the ID for the tab is the same value as the short name you give the page you are linking to.