PWM is a rather lightweight window manager for X11. It has the unique
feature that multiple client windows can be attached to the same
frame. This feature helps keeping windows, especially the numerous
xterms, organized.

Being a lightweight window manager with emphasis on usability, PWM does
not have all the features that one might expect from a window
manager. Those features are simply unnecessary. PWM does not provide
pixmapped themes or other bloated eye candies but has a clean and
simple look inspired by BeOS and Motif. There are no icons and frames
cannot be iconified, only "shaded". Only One True (pointer) focus
mode is supported: sloppy. PWM does not even have titlebar buttons and
may not be the easiest window manager to get into, most Good
Things are not.

PWM does have workspaces, menus and Window Maker dockapp support. It has
pretty good keyboard support and almost all the functionality
is configurable.