GROUPS FILE
       Since version 0.1.11, Fluxbox has a feature  called  auto_
       grouping,  that is apps are automatically grouped together
       if they are in the same group.  You can create groups sim_
       ply by editing the ~/.fluxbox/groups file.  The file takes
       the format of:

            <app1> <app2> <app3> ... <appN>

       where elements can be found with this command:

            xprop WM_CLASS

       Just launch this command in a terminal and  click  on  the
       desired  app after. It will tell you what to write as ele_
       ment.  Each line forms a different group, e.g:

            Navigator nedit
            xterm

       This will create two groups, one with netscape and  nedit,
       and one with xterm.  The new window will only group itself
       to other windows on the same workspace  and  to  the  last
       window that was focused.