If I change it to 'non' the list box is empty.

Well, obviously if you change the RowSourceType of your drop down list, you must also change the way in which you populate its internal list.

I suggest that you move a RowSourceType of 3-SQL Statement and put this in the RowSOurce:

SELECT SomeFields FROM SomeTable WHERE SomeCondition ORDER BY SomeField INTO CURSOR csrListBox 

I am assuming here that you understand tht you must substitute the names of your specific tables, fields, etc. in the pseudo code above < s >.