Sensible defaults
In the wmaker-dev list, Iain noted that:
"I can see the benefit of this. I know of at least two
applications[1] which don't bother to set a class and instance. Early
versions of my OS X cycling patch for Window Maker caused a crash when
faced with such windows because I forgot to check that these
properties existed. Nowadays it just refuses to do the cycling.
Also Window Maker won't let you save attributes on such windows from
the Inspector.
[1] Interestingly they are competiting commercial applications: No
Machine and Exceed onDemand."
[crmafra: edit commit log]