#1779 The event editor modifies by itself the duration of grace notes

[Yves Guillemot]

• Create an empty segment and open it with the notation editor
• Enter a eighth grace note preceding a half note
• Open the segment in the event editor
• The duration of the grace note is 0
• Double click on it to see its properties
• The duration displayed is 1920
• No properties have been edited, so clicking OK should have no effect
• Click OK: The grace note is now a half in the notation editor

[Philip Leishman]

I have a potential fix for this
See merge request.