Just found http://tronche.com/gui/x/icccm/sec-4.html#s-4.1.4
So apparently the help window wants to go into WithdrawnState, get
ignored by dwm, and draw its own icon or whatever right after being
mapped. Makes sense to me...
Mathematica 7 and 8, probably plenty of other versions, and maybe even
some other retarded clients, send UnmapNotify events for their help
windows right after they get created. dwm then forgets about the window
and it's a huge pain in the ass to work with. Don't ask me why, I'm not
drunk and stoned
