Not sure if there is a better place to contact someone regarding
scrotwm; but I'll give it a shot here.
Running scrotwm, built from cvs (scrotwm.c,v 1.302 2010/09/16).
Using a default modkey, which happens to be left alt. When I start
scrotwm, and have my numlock on, modkey doesn't work. It works fine with
numlock off. Yet, if I restart scrotwm using a sighup signal, modkey
starts to work with both numlock on and off. There is no difference in
xev(1) output from modkey+j with both numlock on and off.