message subfile in CL program - 2nd level text

I've got a small brain-scratcher here.  I've got a CL program and a
display file declared in the program.  The display file has several
24x80 screens and a message subfile.

I am using:
   SNDPGMMSG  MSGID(&MSGID) MSGF(&MSGFLIB/&MSGF)
      MSGDTA(&MSGDTA) TOPGMQ(*EXT) MSGTYPE(*STATUS)
to send messages the program receives from commands it executes to the
display file's message subfile.  The message shows up fine on line 24.
However, when I place the cursor on line 24 when the message is showing
and press F1, I am not getting the screen that shows the entire message
with 2nd level text.  Instead, control returns to the CL program.  The
display file has the ALTHELP and HELP keywords defined.  

Just now I tried commenting out the ALTHELP and HELP keywords to see if
that would keep control from returning to the program.  It did, but
instead of the 2nd level help text, I got "Function key not allowed".
Interestingly enough, when I press F1 on *that* message, I get the 2nd
level text screen.

I'm sure I have done this properly in the past, but I can't find the
application where I have done this before.  

Any clues for the clueless?   TIA!

Dan Bale
IT - AS/400
Handleman Company
248-362-4400  Ext. 4952
D.Bale@Handleman.com
  Quiquid latine dictum sit altum viditur.
  (Whatever is said in Latin seems profound.)