Better UI control than CheckboxSetField for selecting items

[sminnee]

Right members / projects / etc are selected with a CheckboxSetField. This doesn't scale well and is a pain point of actually using the UI.

A better UI control, e.g. a list with an autocomplete-based picker, would be better. It's possible that GridField can be used to build this, but would need testing.

[Cheddam]

There are a couple of existing fields that might improve the situation a bit, but aren't super well suited and would require hackery to get them storing data in the right way:

• A GridField with the GridFieldConfig_RelationEditor component attached
• A TagField (this could end up just as unwieldy as the current CheckboxSetField)

Alternatively, we could produce a new field that better suits this purpose. Here's what I've come up with:

The default 'All' filter would show every option, sorted by Enabled first. The ellipsis (or something similar) would expand to display the full list, which could default to ~10 items. Useful for quickly toggling particular items in a small list off, but should still be plenty usable with large datasets by way of the search input.

Happy to PoC it (likely in Vue initially, as I have more experience with that than React). Let me know if you have any thoughts on the mock, and if you think it's worth investing some time to build 👍