Appending an empty option for non-required fields in supler-js, not supler backend. This is a frontend implementation of "no option selected"
Better names for interfaces for rendering fields which can have any value or from a selected list
When a data provider is present, sending both the index and the value (label); when applying, using that index to lookup the real value. That way it is not possible to set an arbitrary value of a select field.
Also creating a new field type - select - which doesn't have number validations, but generates a number