mail not deleted from spool on inc with exmh

["Richard E. Hawkins" <hawk@hawkins.cba.uni.edu>]

I've seen this problem a couple of times before, and it's happening 
again.

My mail is not being deleted from the spool when exmh incorporates it.  
As a result, the same messages are incorporated again and again.  Using 
inc from the command line seems to solve the problem.  Sometimes (not 
always), I end up with an extraneous lock file that survives the inc
orporation, but just deleting this doesn't solve the problem.

I have installed:
ii  biff            0.10-1         a mail notification tool
ii  elm-me+         2.4pl25ME+48-2 MIME & PGP-aware interactive mail reader [en
ii  exmh            2.0.2-4slink2  An X user interface for MH mail.
ii  grepmail        3.4.1-4        search mailboxes for mail matching an expres
ii  mailx           8.1.1-10       A simple mail user agent.
ii  metamail        2.7-31         An implementation of MIME.
ii  mime-support    3.5-1          MIME files 'mime.types' & 'mailcap', and sup
ii  nmh             0.27-0.28-pre8 A set of electronic mail handling programs.
rc  procmail        3.13.1-1       Versatile e-mail processor.
ii  smail           3.2.0.102-1    Electronic mail transport system.
ii  xmh             3.3.2.3a-11    X interface to MH mail system

any hints?

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