[MlMt] Red-dot messages

[John Cooper]

I use both MailMate and webmail every day. Recently, I've noticed that 
when I send a message to the Trash in webmail and then return to 
MailMate, the message still appears in the MailMate app, but marked with 
a red dot. Synchronizing the account does not get rid of the message, 
which must be deleted manually.

I don't remember seeing this behavior until recently. Is it documented 
anywhere?