I’ve been using IceWM on and off for many years now. And because we used it in our UNIX/Linux education environment I did create some patches for IceWM. Some of these patches are now part of the mainstream version and (of course) some are not.
My patch files can be found here.
These patches are mostly focused on window management such as (This list is not complete):
and some are focused on system control (reboot and family)
All these options can be controlled through the preferences file.