Dovecot pigeonhole help sought

[Timothy Murphy]

I'm running postfix + dovecot + dovecot-pigeonhole
on my CentOS-7 home server.
I would like spam to finish up in ~/Maildir/.Spam/ .
Spam is being marked, but is not separated -
it ends up with all the other email in ~/Maildir/cur/ .
Evidently there is some step I have omitted to take.

I give the output of "sudo doveconf -n" below.
The file ~/.dovecot.sieve reads:
------------------------------
# Sieve Filter

require ["fileinto","regex","envelope","vacation"];

if header :contains "X-Spam-Flag" "YES" {
        fileinto "/home/tim/Maildir/.Spam/";
}
------------------------------

When I run "sudo systemctl restart dovecot"
I see the line
  Jul 27 18:54:23 alfred dovecot: master: Dovecot v2.2.10 starting up
    for imap, pop3, lmtp, sieve (core dumps disabled)
in /var/log/maillog

Output of "sudo doveconf -n > dovecot.conf"
------------------------------
# 2.2.10: /etc/dovecot/dovecot.conf
# OS: Linux 3.10.0-123.4.4.el7.x86_64 x86_64 CentOS Linux release 7.0.1406 (Core)
listen = *
mail_debug = yes
mail_location = maildir:~/Maildir
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress 
comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify 
environment mailbox date ihave
mbox_write_locks = fcntl
namespace inbox {
  inbox = yes
  location =
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix =
}
passdb {
  driver = pam
}
plugin {
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/sieve
}
protocols = imap pop3 lmtp sieve
ssl = required
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem
userdb {
  driver = passwd
}
protocol lmtp {
  mail_plugins = " sieve"
}
protocol lda {
  mail_plugins = " sieve"
}
------------------------------

Any advice or suggestions gratefully received.