Currently when using an editable grid and modifying a lookup field, you can only search for the primary field of the lookup entity. It would be nice if you could search on other fields, perhaps the same fields used in the global search.
It would also be good if more than just the primary field was displayed in the lookup menu, like everywhere else in the system that lookups are used.

This is a problem when there are duplicate values in the lookup entity. For example, if I want to add a Contact lookup value using an editable grid, I search for 'John Smith', and my system has multiple John Smiths, I can't tell which one is the correct one.