groff -ms does not diagnose nested .KS keeps. An inner keep is useless, because if it triggers, the containing keep will include a page break, contrary to intent.
There's nothing inherently wrong about a useless feature, but a stray .KS (as distinct from a nested one) like this .KS ... .KS ... .KE can lead to the diagnostic "diversion open while ejecting a page." A diagnostic for a .KS within a keep would be clearer. It seems that nested .KF keeps should be OK. Doug
