I have never seen this before. If I click on a message from the "Mail Browser" window and hit Cmd-P I can print the message according to Macintosh specfications. But if I open the message in a new window, Cmd-P seems to "Print One"--ie, it prints the message without a print dialog. Have others seen this? It appears to be dependent on whether the message is showing plain text or html--plain text messages print correctly, html printing doesn't bring up a print dialog box.
A PM 5.1b3