feature: allow reordering of input fields on the right side of the editor

In the input's editor, there are two sides:  left side (fields displayed in a hierarchical order), right side (simple list of input elements).

It would be nice if the right side could be reordered using the drag handle in the same manner as the left side.  Doing it on the right side would be easier, particularly with long lists of inputs and their respective fields.