Subfile question

I'm having an issue with a converted DSPF36 screen that I'm trying to
convert/use as a subfile. In our customer data entry program, a user can
press F8 to call the NOTES program (a called "RPG" program) which overlays
the notes data-entry screen onto the display. In the S36-style display
file, each notes line of the notes screen is a separate field (15 of them in
total). You remember doing that sort of thing way back in the day.

The boss wrote all of that about 15 years ago, maybe longer, and it's worked
fine for years. Now he wants to me add some new fields to the notes file,
and to update the coding to new style and replace the DSPF36 with subfile
programming. Cool, and it's about time.

I've converted the S36 screen to subfile (2 subfiles, according to his spec)
and written a new version of the notes program (RPGLE, actgrp=*caller) to
populate/display the existing notes in one subfile, and present another
subfile for new notes entry. It's basically working, except that instead of
overlaying the subfiles onto the customer data-entry screen, the display is
cleared and then the subfiles data-entry screens are displayed.

I've tested and tested it all kinds of ways. The most-recent test was to
modify the customer data-entry screen to include the notes populate/display
processing within the customer data-entry program. It does the overlay just
as I want - the SECOND and subsequent times that the notes screen is
displayed; the first time thru the display is blanked and the notes screens
are shown.

I'm not sure what I need to adjust to get this to properly. Any ideas?

TomH