When using the authority.ftl form control in a search form, the layout is rendered all wrong.
Layout should be a normal association selection box with a search field on the top and two boxes side-by-side underneath. The left box should have the search results and the right box should contain the selected users.
See attached screenshot.
1. Define a type or aspect with a person association:
2. Define a search form for this type, include the field
3. Optionally declare for the field to use the authority.ftl form control
4. Deploy to Share and open the custom search form.