Hm I've tried to make an example, but it in fact works with (IGNORE_SPRITES | IGNORE_MODELS | IGNORE_WORLD) set. If you haven't changed c_move since ~January 2011, I was simply wrong - although I remember the issue as if it were yesterday.
Ok, then I will (continue to) use c_move with the said movement mode.
"Falls das Resultat nicht einfach nur dermassen gut aussieht, sollten Sie nochmal von vorn anfangen..." - Manual
