Thanks. Committed as r1937.
Use side-by-side filterable lists for Users in the admin UI.
Review Request #840 — Created April 27, 2009 and submitted
This adds the filter_horizontal attribute wherever the User list is presented in the Admin UI to better deal with large lists of people. I didn't feel like this was necessary for the Groups listings (we only have 11 groups at my company). But I imagine it could be useful for those fields as well, feel free to add that.
Brought up admin UI, made changes to these fields, seems to work nicely.