BUG/Problem: Mail Format doesn't take effect

Even when I set Compose, Mail Format (see below picture) to plain text, when I compose emails, I noticed that it is sent with formatting. Of course, because of the ridiculous bug in emClient, this formatting is completely screwed and looks unprofessional by the recipients.

Specifically, when I compose email, and make Bold some words, the email is sent with formatting. So this behavior is inconsistent. If I asked not to include formatting in composed emails why would it let me use formatting anyways?!