FVWM-Crystal is a theme framework for the FVWM window manager. It uses GUI tools to edit the look of windows, instead of the use of editing a text file in FVWM. It creates a desktop environment using FVWM as its window manager and main core.It features flexible window decorations, and a file manager may be optionally used to display desktop icons; ROX-Filer, Thunar and Nautilus are supported for this task.