Selecting controls during script editing

Good morning,
Quoting your documentation : clicking an input in the MIDI Controller Area will update the ‘Controller Input’ selection.
Unless I missed something it works here when editing the controller template but does not work when editing a mapping. Is it something planned in the future ?

One additional question : What is the purpose of the pale blue color which replaces the grey color on buttons when clicked in the controller template view ?

Thanks for you answer and best regards