Hi Priya,
Can go through TCODE: SE51 (Screen Painter) for the Z program and check whether your selection screen updated or not.
If the selection screen is Ok in SE51 then the second option is to do the below steps:
1. Delete entire selection screen and save the program without selection screen.
2. Re-built the selection screen again and save the program.
Hope it will be helpful.
Thanks & Regards,
B Raghu Prasad