fvwm

FVWM (F Virtual Window Manager) is a highly configurable window manager for the X Window System. It provides the core functionality needed to manage application windows and is designed to be extended through modules and a scriptable configuration. FVWM aims to be fast and lightweight while offering extensive customization, allowing users to implement tiling, stacking, or hybrid layouts, as well as custom menus, panels, and desktop navigation.

Its behavior is controlled by a plain text configuration file, typically .fvwmrc or a FVWM2-style file. Users define key and mouse bindings, window rules, docking and panel elements, and actions triggered by events. The window manager ships with a suite of modules—such as FvwmPager for virtual desktops, FvwmTaskBar, FvwmIconMan, FvwmIconBox, FvwmButtons, and FvwmMenuTheme—that can be combined to produce a complete desktop environment. A rich set of configuration options enables automated placement, focus policies, title decorations, and dynamic behavior based on window type or class.

History and variants: FVWM originated in the early days of the X Window System and evolved through several major revisions and forks, including FVWM2 and FVWM95 variants. Its modular design and scriptable configuration influenced many later window managers and desktop shells.

Usage and status: FVWM remains in active use by users who value fine-grained control and a lightweight footprint. It is included in many Linux and BSD distributions and can run on a wide range of X11-compatible systems. While less common in mainstream desktop environments today, FVWM continues to be developed and maintained by a small community and remains a notable option for customized window management.