title: Observable collection with current item?
body: <p>In a dialog from my application, I have an observable collection (stored somewhere else) bound to a list of tabs. When I close and reopen the dialog, the currently selected tab gets lost and winds up to the be the first one. How do I set up my tabs so that the selected tab persists?</p>
  
  <p>I had the impression that the observable collection had "current item" property, but that doesn't seem to be case. I've looked at ItemCollection and CollectionView, which do have a current item property, but I'm not sure if that's that I'd be interested in.</p>