[imp] Convert messages to plain text

[Michael Wisniewski]

I have a stupid question that I can't seem to find the answer for.   
When reading some messages, I get the following...

This message part contains HTML data, but inline HTML display is disabled.
View HTML data in new window.
Convert HTML data to plain text and view in new window.

Nowhere am I able to find the setting to automatically convert HTML to  
plain text or enable inline html.  Does anybody have an idea of where  
I can find this?

Thanks!