Marked UDF in the pick and pack mask is lost

Hello everyone,
I have a question that hopefully someone can answer for me.
Our customer has stored a UDF in the Pick & Pack mask, which he would like to see in the view. He can activate it in the form settings. Then it is also visible. After he closed the window and opened it again, the UDF disappeared again. I was of the opinion that this stays when the field has been activated. How can I fix this? In my version FP2208 I was able to reproduce the problem.

Thank you in advance for your active support.

kind regards
René