The window is only as good as what the object exposes. Three settings turn it from three identical rows into a usable record picker.
- Confirm the fields are searchable
From Setup, enter Search Manager in the Quick Find box and select Query Configurations. Check that the object and any custom fields you care about are switched on.
- Open the object's search layouts
From Setup, open Object Manager, choose the object, then select Search Layouts.
- Edit the Search Results layout
Use the dropdown across from it and select Edit. Move in the fields that separate near-identical records, such as Phone, Billing City and Owner.
- Test it from a real lookup field
Open a record with a lookup to that object, type two characters, click Show more results, and check that a distinguishing value returns exactly one row.
Sets the columns this window shows for the object.
Salesforce Classic only, and only where enhanced lookups are enabled.
Sets which objects and custom fields are searchable at all.
- Field-level security still applies, so a field a profile cannot read will not help that profile tell two records apart.
- The window only searches the lookup's target object, so a record filed under the wrong object will not turn up however you tune the layout.
- The window returns at most 200 records by relevance, so an over-broad search can bury the record you want.