Suggesting to add BUTTON in the PopUp to run the corresponding expression, instead of returning it everytime PopUp is loaded.
For example PopUp is open and shows 3 lines of main info and a Button. After Button is pressed it will run an expression and pull additional info with more details. In this case PopUp doesn't have to collect the large amount of data everytime while being loaded and can load the additional info only when needed.
This can help to improve the productivity and overall end-user experience.