[DTV]

More reasons than I can be bothered listing, but the cream / black images on a washed out screen in a bright white and red set is a particular highlight.

Smart glass is one of those things that seems like a great idea for a news set, until you actually have to use it - particularly as having projectors 'open' and competing with studio lights is only going to create a weak picture at the best of times. They were going to use it again in Studios C and E when they moved to NBH, but luckily realised it didn't work in the piloting stages and replaced them.

In fact, you can actually still see them (and their much weaker image) in The World's Newsroom trailers.
www.youtube.com 

It's also why you're left with the weird lightbox arrangment in the over-the-shoulder shots, the small white lightbox would originally have been where the projectors would have gone. (Image from TV Live)