A live stream on Thursday from Microsoft's Xbox Live programming leader Larry "Major Nelson" Hryb showed a version of the Xbox One user interface with what looks like transparent tiles, similar to what's already available for Windows Phone.
An image from that live stream was later posted on Reddit, and it does show that the background is popping out of the Xbox One's home screen tiles. Since he works on the Xbox team, Hryb likely has a preview version of the Xbox One UI that is not yet available even for people who have signed up to beta test upcoming features for the game console.
Keep in mind that even if Microsoft is testing transparent tiles for the Xbox One, it may take a while before that feature is released to the public. Indeed, we already know that a promised feature that would enable owners to take screenshots directly from the Xbox One has been pushed back until sometime in 2015.