How to bring dropdown at top

Question

I'm not getting this dropdown in front as i have created a custom control combo of tree behaviour.

Answer 1

By reference to this doc: Add a custom field to a work item type (Inheritance process), we can add a custom field to support tracking data requirements you have that aren’t met with the existing set of fields.

Currently, the field Area Path and Iteration Path are existed datatype as Tree path, but their value are defined in Project configuration page and Team configuration page by reference to this doc: Define area paths and assign to a team and Define iteration paths and configure team iterations.

However, tree type is not available in new field, as below.

In addition, this is indeed a good suggestion. You can create a suggestion ticket here. The product group will review these tickets regularly, and consider take it as roadmap.