You have Static lookup and would like to see the Name and Description when making a selection.
Steps to Reproduce:
Result: only see Name and no description in the drop-down in lookup.
In the out of box Track Mode static lookup same thing happens, not able to add Description to the lookup
The Clarity Dynamic lookups seem to have the header and support so we can add the additional columns.
Clarity
Per Product Management, this is working as designed, the ability to use the autosuggest has only been implemented for lookups that use a dynamic query. There might be opportunity to put this in a future backlog but for now it's not possible to configure on static lookup.