I have a list on a site that was created by importing an Excel spreadsheet.
I have several lookup columns that were deployed to the site using a feature. Going into the site columns gallery, I see them all there, and they look to be set up correctly.
I have several other lists that use the lookup columns, also deployed with the same feature, pre-populated with items. Going to those lists, I see the all the items as expected and the lookups are correctly connected.
(The feature basically sets up the back-end for
SPServices cascading dropdowns.)
When I go to add the lookup columns to the list created by importing the Excel file, they seem to add without issue. They are listed among the existing list columns, and identified as lookup columns.
When I open the Edit form, however, the dropdown controls are not rendered. The labels for the fields are on the form, but there's no actual control to use to choose a value.
As a test, I did create a brand new custom list, added my lookup columns, they worked fine on their own, then I added the SPServices script, and the cascading dropdowns worked as well. So I know it doesn't have to do with the columns themselves, it's very specific to this other list.
After doing some more testing, I can see that after adding the columns to the list, they are added correctly to both the Schema XML of the list, and to the Item content type on the list. Everything seems in place for the fields to be included on the Edit form, and indeed they are (like I said, the labels are there, just not the dropdown controls).
What could be a reason for the dropdown controls not rendering?