[MlMt] Inbox vs All Messages

[Robert Brenstein]

I have a smart mailbox which is set to show messages sent to, cc, bcc, 
from, resent-from a specific domain. When I set it to check Inbox (in 
the Mailboxes tab), I see 2867 messages. When I set it to check All 
Messages, I see 3121 messages. However, when I see it to check the 
source, I see 3157 messages.

I expected All Messages to show me more messages than source, because it 
should include messages that I sent to users in that domain from my 
other accounts. The source includes messages in trash and spam mail. I 
expected All Messages to include those as well. Apparently, All does not 
really mean all.

Is there a description of those standard mailboxes in the documentation? 
I can’t seem to find it.

Robert