Backport to 11.2: In the document editor, red invalidation markings do not move together with an invalid compound

Given a document type with a multiple, ordered compound, and the compound has a mandatory string field.

• add two compounds to a document, leaving the mandatory field of the second compound empty
• try to save: red markings appear on the second compound
• move the second compound up

Expected: the red invalidation markings stay on that compound (now first in order)
Actual: the red invalidation marking stay in place and are now on the first compound (now second in order)

Also see the original issue.