Heck from what I remember, half of the compsiting stuff that's done now with compiz/kwin in modern desktops was pioneered with E17 development, they used Xgl be

Heck from what I remember, half of the compsiting stuff that's done now with compiz/kwin in modern desktops was pioneered with E17 development, they used Xgl before the accelerated compositing was possible with GLX_texture_from_pixmap and the like.