Registers (or, with null, unregisters) a field's row element on the panel side.
Selects a field and brings its row (pdf, link) or its box (panel) into view; null clears.
Sets (or, with null, clears) what to do when a panel selection's box is not mounted.
Registers (or, with
null, unregisters) a field's overlay box element on the PDF side.