Enlightenment (Window Manager)

Enlightenment (also known simply as E), is a free software/open source window manager for the X Window System. It can be used alone or together with a desktop environment such as GNOME or KDE. Enlightenment is sometimes used as a replacement for a full desktop environment.
History.
The first version of Enlightenment was released by Raster (Carsten Haitzler) on 1996-10-30.
Enlightenment has been under development for 10 years. Its latest stable release is E17. It always comes with a warning that it is in permanent "heavy development" and remains "not stable".