An example is: a gallery has an exhibition starting on Feb. 4 and ending on Feb 25. But the gallery is only open on Saturday. What happens is that the user enters 2023-02-04 as a start date and 2023-02-25 as an end date. <em>Then</em> he clicks on the repeating field to indicate it is a weekly repetition until 2023-02-25. This end date is already prefilled based on the end date of the event, so the user is in an assumption that he has done it correctly. Also there's no warning that the end date of the first event and the end date of the repetition are the same and that this is not possible.
It would be nice if some kind of JavaScript would do a check on both end dates if the repetition is opened and show pop-up a warning if both fields are the same. Maybe with some message indicating that the end date of the event should be the end date of the first occurrence. (Like I've set now in the language override)
I can imagine that it is quite difficult. Since there are more scenarios. The end date of the first occurrence doesn't necessarily have to be the same day / start date. Not only because an event can last two days (the exhibition can be on Saturday <em>and</em> Sunday), but also an event can start at 10 pm and last till 2 am the next day.
(In general events round midnight are quite 'interessting'. Events that start after midnight are technically on the next day, but for an end user who is planning his night out the 'day' ends when he goes to sleep, which can be 4 am. The new day for end users who wake up should start with morning activities, not with activities in the holst of the night. But this a different topic.)