[MlMt] Multiple rule interactions (was "Re: Filter(?) Message is moved to trash")

[Randall Gellens]

I have some accounts where the Inbox rules are first a set of rules that 
each check for a certain value in a header field (often, the 'List-ID' 
field), and if so, add a keyword to the message and move it to a 
list-specific mailbox. Then there's a rule that, if the the 'To' and 
'Cc' header fields do not contain my address and the keyword added by 
the earlier rules doesn't appear, then move the message to a catch-all 
mailbox. The intent is that the messages left in the Inbox were 
addressed to me, messages for certain lists I care about are moved to 
their list-specific mailboxes, and everything else is in the catch-all 
mailbox.

However, what ends up happening is that messages are moved to the 
catch-all mailbox despite an earlier rule moving them to a list-specific 
mailbox (as evidenced by the keyword having been added). Are rules 
processed in an aggregate way, so that an earlier rule that moves a 
message is counteracted by a later rule? And an earlier rule that adds a 
keyword doesn't actually add it until after all rules have finished, so 
that other rules can't test it?

--Randall