In condition you put one more criteria so that it will fire only for pick skip note is NULL
PICK_SLIP_NOTE IS NULL
the firing part is ok. The problem that we are facing is, it doesn't save the changes to database.
There may be some code in the form which defaulting the value and overriding your customer text.
Have you verified it at database level too?
We think not likely is because
if we enter some value in pack slip note, eg: we put 123456
then we move to next line, then we see that the form personalization is working by replace the 123456 with the text that we want to default.
Then we click 'Save'.
then we reload the sales order, and the value appear in pack slip note is 123456 !? (and not the text that we want)
we kind of solve this problem by:
1) in form personalization, after the properties rule, we add another rule to call the custom library.
2) in the custom.pll, we call the following procedure: