I have a number of existing entity reference fields in my site. The key one is a taxonomy reference field called
field_search_terms. I would like to add this field to the
Document media type. However when I go to manage fields for the media type my existing fields are not available.
It looks like I need to create a new field and any search that mixes content and media will need to have two filters.
Why is this limitation in place? Is there an issue I can follow to learn more?