IceWM

X11 window manager

IceWM is a stacking window manager for the X Window System, originally written by Marko Maček. It was written from scratch in C++ and is released under the terms of the GNU Lesser General Public License. It is customizable, relatively lightweight in terms of memory and CPU usage, and comes with themes that allow it to imitate the GUI of Windows 95, Windows XP, Windows 7, OS/2, Motif, and other graphical user interfaces.

This keyword could refer to multiple things. Here are some suggestions: