Mail can't sort by color anymore.

[Whitehill]

After upgrading to Lion, Mail 5.1 can't sort the message list by color, although it can display the color. I use SpamSieve and it colors messages in the spam folder according to its confidence that a message is spam. Yellow is lowest confidence. Before the upgrade, I would sort by color and take a quick look at the yellow ones, before deleting everything.

Is this another personal problem?

Evidently not. See this discussion.