Hi @WarrenBelz,
I was afraid that I will receive answer such this. But anyway, thank you very much for your confirmation.
EDIT:
For anybody else, who will encounter the same issue - I implement a kind of work-around in my solution:
1. I removed the particular form field from edit form menu.
2. I added a new (empty) drop-down list to my edit screen manually.
3. I populated list items in that drop-down (manually as well).
4. Lastly, I used a patch function to update my data source with selected data from that drop-down.
Maybe it will help someone too! 🙂
