Sort lookup values in a drop-down list control

Hello people from the community,

I'm new to NF2013 and maybe my question will be to simple for many of you, but I searched the forums and did not find any response to my problem.

I have a form with cascaded lookups that works fine for selecting values, but the second drop-down list show values unsorted.

I controlled my columns in both lists, and the default view for each view is well sorted. But NF still shows the data in the order of entry (aka by ID), i didn't find any way to have them sorted alphabetically.

Any help will be gratefully appreciated.

Filippo