treewm is a window manager that tries to implement a new concept. In
addition to the client windows the user can create desktops which can
themselves contain windows and desktops. By arranging the windows in
such a tree the user is able to manage his tasks efficiently treewm is
feature-rich, flexible and provides a powerful concept. However,
treewm's look is is rather puristic, and its feel is not always
intuitive, but with a bit of practise it should be very effective to
use.

Short feature list (some of them are quite unique among window managers):
  - Allows to create desktops and to arbitrarily move windows between
    desktops
  - Many options (such as sticky, autoresize, always on top, or the
    focus or raise policy) can be set for any desktop or window
  - Can be fully customized using the configuration file
  - Has a very powerful (somewhat vi-like) command mode, and can be
    controlled from shell scripts via a FIFO
  - Icons can be placed on desktops that can execute arbitrary commands
  - Only uses very common libraries, in particular it doesn't require
    GTK, Qt, or anything like that

WWW: http://treewm.sourceforge.net/