And when I did M-d on a mail already marked with "O", I got exactly
the same result as spam1-debug-statement above.  Therefore, I guess
something deletes spam mark on a mail previously marked with "O" when
I exit the summary buffer.  But I have no idea what it is.  

Ted> Again, sorry that I can't find the problem, but it's happening
Ted> only for you, so you have to do the hard work :)

You are not sorry.  I really appreciate your help.  :-)

>> What does "33" mean?  ham?


Ted> (format "%c" 33)

Ted> to find the visual representation of any mark. 

Thank you very much for teaching me so much.  

--
Kohkichi Hosoda
E-mail address: khosoda@venus.dti.ne.jp
http://www.venus.dti.ne.jp/~khosoda/Enlightenment.html