Apple Mail 1.3.11 running under OS X (10.3.9).

(Interested parties are invited to try this, with a message they plan to
delete anyway.)

View a message in the Inbox (in the pane under the one showing lines with
From, Subject, Date, etc.). Highlight (select) some text. Go to the Edit
menu and choose Delete.

The entire message disappears. Go to the (Mail program) Trash. There is
the message. Now select another folder, then go back to the Trash.

Gone! Does anyone have any idea if it can be recovered--and how to do it?
Is this a known bug?

Thanks for any information.