Extra day is included in an all day event when created by selecting a section of the calendar

[ane-gabriela]

Seems that #55 is still reproducing.

Steps to reproduce:

1. Select a period eg. 3 days in Calendar view
   

Expected results: The Start and End date correspond with the selection the user made.

Actual results: One more day is added to the End date.

Environment: Windows 10, XWiki 12.5.1 with MySQL 8.0 and IE 11, Firefox 94, Edge and Chrome 95, Calendar Application (Pro) 2.10.1

[ClemensRobbenhaar]

The fix for issue #55 took only the display of events into account after they are created.
Fixed for event creation, too, in 6827690

Edit: forgot to say the fix should be available in 2.11

[lucaa]

This was a complex issue when it was fixed for #55 , because of the way calendar events are handled by fullcalendar: the endtime of a calendar on fullcalendar is considered to be exclusive, or something like that. I don't remember the exact details, but I remember it was not easy to actually find a way to conciliate the all day events and the events that have a time specified.

For an event with a specified time, when it has start date 15h00 and end date 16h00, you actually assume it takes 60 minutes, starting with minute 0 from hour 15 and ending with minute 59 of hour 15 (so, until 15:59 inclusive and excluding 16h00).
However, for an all day event, we apparently don't accept that the end date is 21/10/2021 00:00, exclusively (by the same rule as above). So an exact 72 hours event won't stop at 18/10/2021 00:00 and end at 21/10/2021 00:00 (exclusively) but somehow stop somewhere in the day of the 20th (how?).

So I think because of these difficulties there was some decision made that made sense to end the all day events the day after. I'm not saying it's necessarily a good idea, I'm saying we need to define a rule that works, and potentially for which a 24h event is equivalent, in terms of start date and end date with an 'all day' event. On this topic always assume that the risk that a new bug is introduced when some bug is fixed is high.