When configuring ReviewBoard is really easy to loose track on which tab you are, since there was no visual cue to that.
There was a css class already in admin.css called '#admin-subnav li a.active', but it was never used.

So I hooked it up in the code, so it stared being used. But then it clashed too much, and the tabs didn't feel like tabs. So I changed it to include a background and a border so users can instantly recognize where they are.

Since the breadcrumbs part has a little gradient, I had to expand that gradient otherwise the background clashed.

Tested result in Safari 4.0, Firefox 3.5 and 3.0 and Chromium Nightly.