Thanks for the reply, TKP.
OK, I see that you need to press the ALT key when using the Smart Tool to create the note and then can edit it with the same tool according to where the mouse pointer is relevant to the note.
However, the first sentence in my previous post is still valid. I have to select a note duration to change note lengths as stated in the help file:
Note: Use the Value control in the Tools module to specify the duration for new note events.
In 8.5, clicking on an existing note would change to that duration. That is much quicker when adding notes of different values. I don't see a way that can be done in X1 but am still hopeful.