HTML Message is Lost When Returning to Create Content from Test Step in Send Mailing Wizard

If you using the Compose Method, create an HTML message, go to "Test" and then click Previous - the Editor box is empty (your message is apparently "lost" - and you would have to re-enter it from scratch).

(The message body is actually not lost - it's saved to the mailing record in the DB - but is not reloaded to the editor.)

Folks need to be able to compose -> test -> compose so they can tweak/fix stuff after previewing and or sending a test mail.