Currently, in Gantt, if the start date and end date are the same, duration is recognized as 0. If the start and end dates are the same, can the duration be expressed as 1, and the graph on the right can also be expressed as 1 day? I would like to apply the same when editing the end_date and duration with the inline editor.
Gantt uses the non-inclusive duration. There is no way to change how Gantt works, but you can change what is displayed to the users by using the templates:
Here is an example of how it works: