Pegasus and HTML

I resort to that great tech help, the SDMB.

Pegasus v4.
If my user highlights her text and then selects UNDERLINE, some users receive HTML code. She types her email address, highlights it, selects underline and apparently Pegasus tries to send HTML, but the HTML code is received. Cut, paste and rename TEXT.HTM, and it is HTML code with a “mail to” for her address.

Same when another user highlights his text and changes color.
How does Pegasus handle HTML?

Thanks