Screenshots of this build were included in a patent filing describing a multiple-mode window system. The multiple-mode window system basically is the effect you see in Longhorn (and indeed later in Vista RTM as well) when a maximised window turns from transparent to opaque and the other way around when restoring. Funnily enough this effect was completely abandoned by the time Windows 7 was released. The images show working DWM and Aurora in the preview panel. The original patent was first filed at 24 October 2003 under the name of Multiple-mode window presentation system and process with patent number US 7199802 B2.