Hi,
I am sorry that the logic of operation is unclear; with the goal of eliminating all the superfluous the idea is as follows:
if I enter the name of the new note, the button creates the note
if there is no name for the new note, I want to delete the selected note

it is likely that the next versions will implement different buttons to add or remove notes


update 30/11/2017
Thanks for the feedback Ospite dc32fa, a careful analysis led to the discovery of an abnormal shift that occurred in particular circumstances; resolved in version 2.7.5