Fvwm supports session management according to the X Session Management Protocol. It saves and restores
window position, size, stacking order, desk, stickiness, shadiness, maximizedness, iconifiedness for all
windows. Furthermore, some global state is saved.

Fvwm doesn’t save any information regarding styles, decors, functions or menus. If you change any of these
resources during a session (e.g. by issuing Style commands or by using various modules), these changes are
lost after saving and restarting the session. To become permanent, such changes have to be added to the
configuration file.

Note further that the current implementation has the following anomaly when used on a multi-screen display:
Starting fvwm for the first time, fvwm manages all screens by forking a copy of itself for each screen.
Every copy knows its parent and issuing a Quit command to any instance of fvwm kills the master and thus all
copies of fvwm. When you save and restart the session, the session manager brings up a copy of fvwm on each
screen, but this time they are started as individual instances managing one screen only. Thus a Quit kills
only the copy it was sent to. This is probably not a very serious problem, since with session management,
you are supposed to quit a session through the session manager anyway. If it is really needed,

Exec exec killall fvwm

still kills all copies of fvwm. Your system must have the killall command though.