FVWM is a multiple large virtual desktop window manager with very modest resource consumption but highly configurable. Once configured it will suit working habits like no other window manager.
It conforms to virtually all modern desktop specifications, supports transparency and antialiasing in every component. The backgrounds can be set on a per-desktop or per-screen basis with one of the many included modules.
These details are provided for information only. No information here is legal advice and should not be used as such.