[MlMt] Correct default contextual from behavior

[temjeito]

In a few (unfortunately very common) cases, MailMate has learned the 
wrong “From” address to use with certain contacts.

I email client at example.com 10-20 times/day. emails to client at example.com 
should always come from me at thismail.com, but whenever I add 
client at example.com to the “To” field, it changes the “From” to 
him at thatmail.com.

Is there any way to reprogram the default sender for a particular To 
address?

Thanks,

Michael