Windows Longhorn build 4050 (private/lab06 demo.031022-1934)

Windows Longhorn build 4050 (private/lab06 demo.031022) is a private build of Windows Longhorn. This build was shown during the PDC 2003 and is known to have Aurora and Aero transparency. During the demonstration Hillel Cooperman showed the new Aero transparency, which more than 40 people worked on for over a month, and also opened an MS-DOS application to prove that this was not a concept but a real build. A copyright notice at the bottom left of this build can be seen, ''©, TM Microsoft Corp. All rights reserved. User interface is ™ and trade dress of Microsoft Corp.'' On the BetaArchive topic "Why is Longhorn 4057.private/lab06_dev_ux.031107-1900 fake?" ReflectiaX replied that he had some private builds from around the PDC 2003 time, including this build and the instructions on how to prepare it for the demo. This could mean a leak could happen in the future.