Replace _parent_ expression with direct field on sale and purchase line
Since #12003 (closed) lines can be edited outside the parent form so expression should not rely on parent.
Closes #12109 (closed)
This instance will be upgraded to Heptapod 18.6.0 (final) on 2025-12-16 between 09:30 and 10:30 UTC+1
Since #12003 (closed) lines can be edited outside the parent form so expression should not rely on parent.
Closes #12109 (closed)