Put 10.5's help windows in the background

Amongst all the nice changes introduced by the release of OS X 10.5, one of the
not-so-
nice changes in Leopard is the implementation of the help system. In 10.5, when
you call
up help (for a program that uses Apple's help system), the help window opens in
floating
mode -- it's always the frontmost window, and covers anything that happens to
fall behind
it.

http://www.macworld.com/article/133814/2008/06/105helpbkgnd.html?lsrc=mwhints