Plugin Screen customization: Selection list behaviour

Hello

with the plugin screen customization i have changed the form "action". i have inserted a field (see attachment).
if i open the standard field "responsible", then i see no entries (because i have not preselected a project), which is the corrrect behaviour.
if i open the new field "responsible2", then i see all the defined resources.
i would have expected the same behavior like the standard field "responsible".

thanks for your answer
Norbert

i have additional question: how can i create a new section

same behavior (see attachtment)