The DOM:document.evaluate page makes some statements about the behaviour of snapshot results which are wrong. I added the basic problem to the talk page above, and the spec linked from the article has the right behaviour, too. This needs some tech-writing skills, as the spec is apparently too hard to grok here.
I've rewritten the relevant paragraph. Let me know if it seems reasonable.
two weeks and counting, Change by Sheepy (url: http://developer.mozilla.org/en/docs/index.php?title=DOM%3Adocument.evaluate&diff=31778&oldid=13090) seems to have fixed this. Reporter (Axel) if this is not fixed, please re-open and state why.
Yes, this is good now. Thanks.