You can define calendar entries with start and end dates. Currently, the automatic default duration of a new event is two days. However, this is not what you need most often. If you only want to set an event for one day, you have to correct this manually each time.
Simply omitting the column for the end date or defining it as “blank” is not a solution, because then it is no longer possible to define events for multiple days. Setting the option for new rows in the end date column to “Start Date” also has no effect (although it should).
So you always have to change the dates for a daily event manually, which is unnecessarily cumbersome. The default duration for a new event in the calendar should therefore be 1 day and not 2 days.
Note: Coda’s default duration for events used to be 1 day, unfortunately this was changed intentionally or unintentionally at some point.