Impossible to set precise boundaries on this one. Partly, there's the old dictum that comedy = tragedy + time, partly we're all just complicated. I'm probably not the only person who's been moved close to tears by a tragic news story, then snorted at the jokes about it on pretty much the same day. Or maybe I am, who knows?
Anyway, I've got an absolute snorter that covers two of the above mentioned, which I'm assuredly not posting here. PM me if you're just as sick and confused...