Question
Is it possible to configure a block on file deletion from the File type field while still allowing file additions?
Answer
Yes, this can be done by enabling the field parameter Filename with hash at the end
and adding action code for the field on change.
Action code on change:
=: if(condition: $minus != $#lc; then: $err)
minus: listMinus(list: $#onfv[[file]]; list: $#nfv[[file]])
err: errorException(text: "You can't delete files")