Using fluxconf
From Fluxbox-wiki
[edit]
what is fluxconf
fluxconf is a tool to configure fluxbox's init file, edit the menu and the keys file. Keep in mind that this application is rather old and doesn't support all of the new features that were added to the code over time.
As far as I know it is no longer maintained and seems to be buggy too.
A nifty alternative to the menu configurator is Zan's fluxMenu application.
Most of the options that are set in the init file are configured via the config part of the rootmenu.

