I think what @andreas seeks is a way to spawn a new Note by selecting a section of $Text of an existing Note.
It seems he would like to have the selected portion constitute the $Name of this created Note, and have all the $Text that follows it belong to the newly created Note.
The issue I had experienced wrt the Return/Enter key functionality related to the fact that hitting it after making edits to the Note’s $Name, which (post v10.0.1?) had the net effect of creating a new Note instead (unintended behavior).
We had a couple of threads going on this between main forum and BackStage. One such thread is here: Tbx 10 - Changed Arrow and Return/Enter keys operation
I can see the merits of what @andreas requests, it’s a timesaver for some. However as regards the result of hitting Enter while cursor is in the $Text field, I believe all that ought to do is ^CR.