Seems you can’t take screenshots of iTunes-purchased video anymore in Snow Leopard.

This isn’t an iTunes 9 thing either — iTunes 8 shows the same behaviour, but taking shots of video clips isn’t something I regularly try to do, so I guess I haven’t noticed it until now. It’s also worth noting that even Quicktime 7 (on Snow Leopard) provides the same result.

Videos I’ve encoded myself or downloaded from other sources work fine, so it’s definitely a DRM issue.