The Desktop Composition Engine was the desktop compositor in builds 3683-4029 of Windows "Longhorn". It provided numerous visual effects, such as twirling windows while they were minimized. The compositor is present in Milestone 3 builds: 3683,3706, 3713, 3718 and 4001. It also present in later builds,4011 and 4015. In Build 4008, it is corrupt.
One of the most well known visual effects of the DCE is present in certain 4015 and 4018 builds(Lab06). It every build that has it, it makes even the menus transparent, and even the screensaver.
After development reset it had been renamed to it's well-known name Desktop Window Manager. However, starting with Longhorn M7 development, many DCE references, such as DceStartup, were being changed to reference DWM.