The relationship interface is fine for handling a few (<10) elements, but is a nightmare for users as soon as you have many (>50) elements.
GUI things that need to be fixed:
– [Critical] On left column, hide already selected elements instead of gray them. (right now, you have to scroll through element to spot the missing one that is black instead of gray , with lazy loading in the mean time, very painful)
– Add a “Add all” / “Remove all” button
– Search Logic should filter/search on both columns, not just on the left one.
– Filter taxonomy should filter on both columns, not just on the left one. (I had many user feedbacks on this one)
– Ability to reset custom ordering by Alphabetical Order (and maybe by any Post type filed, like creation date ; ASC+DESC). Use “Post Types Order” plugin inspiration.
Thanks a lot
