[ic] Modify "Promotion" page - add fields

[Russell Mann]

Hello,

In IC 5.2, I have a couple of extra fields in my "merchandising" table.  The
problem is I can't access them through the UI under "Promotions."  How do I
add editable fields to this page?  For the item editor there is a place
where you can specify which fields show up, but no such luck for the
Promotions editor.

I see there is a hidden form element called mv_data_fields on this page, but
even after picking through Editor.pm I can't figure out how to modify it.

Thanks,

Russell Mann