You have an interactive program - say PGMA - that calls PGMB. PGMB is supposed to pop up a window to overlay the screen from PGMA, but instead it completely removes that screen. You try the overlay keyword, but that does not help. Is there a solution? Yes.
Add a DUMMY record format to the display file used by PGMB. The dummy format should have the following record level keywords: KEEP, ASSUME. Since ASSUME needs at least one output field, code a blank output field. That is all you need to do. You DO NOT have to reference the DUMMY record in any of your programs - it just has to be there.
Go try it, and good luck.
A R WIN1
(your pop-up window as you want it)
A R DUMMY
A 2 1' '