Thank you for your post.
Create a script named "Exit Pop-up" with the script steps:
Commit Records/Request [ No dialog ]
Then, in Layout Mode, click the field, pull down the Format menu and select Set Script Triggers... Select the last option "OnObjectExit", and select the Script "Exit Pop-up".
Once you enter the field and select a pop-up value, the script will kick in and close the Pop-up.
Let me know if you need additional clarification.
Works like a charm!
Thanks so much!