Setting an EpiFilter on a dropdown list

When a Sales Order is created, all revisions can be selected for a part even if they are unapproved. When I looked at the revision dropdown I noticed that it is possible to filter the list. I tried adding Approved = ‘1’ but it didn’t work. Any suggestions?

We have decided not to go this route.

I would NOT expect that field to be a string.

did you try:
Approved = 1
or
Approved = true
?

I did try it without ‘’, but did not try true. I am actually going in a different direction now.