Evolution doesn't show the contents of the messages

Evolution gave me an error but I didn't read it through because I though I was just opening two Evolutions at the same time by accident. But after that Evolution doesn't show the contents of the messages (except for clicking the mail when a pop-up opens) and it's not possible to minimize or maximize the message window. It looks like this: www.iki.fi/sonja/evolution.png (I sensured the senders)

What an earth did I do?