We are using Batch Update widget to update attributes on several polygons at once. We have list drop downs for various attributes.
For batch update to work we have to have at least one polygon filled with all attributes. Only then can we can use batch update widget.
See below "no value" as neither of the polygons had any data filled in. If one of the polygon had that data in, it would have shown specific drop down list.
Not sure if this is how widget is intended to work.