After getting frustrated by dropdowns not even rendering for the lists with more than 5000 items, I take on a journey.
Idea is using a cascaded dropdown to keep item count to be populated under 5000. Since SharePoint does not even create the dropbox in this case, I decided to create it from scratch, where the error message is displayed using a select statement like
<select id="Primary_x0020_Contact_1bc5bbf8-a68b-48a0-a2e8-8f67c83da0c6_$LookupField" title="Primary Contact">
I looked up field ID manually using this method.
Dropdown gets created nicely and I populated it using an Ajax query with relevant ID/Value pairs.
Problem is that, when I submit the form, it does not get saved.
Is there another magic, other than using the correct field ID that I need to add to the mix ?