eventContent rendered loop after event drop on React <18

[Arithmetics]

Reduced Test Case

https://codesandbox.io/s/fullcalendar-issue-forked-xfuus9?file=/src/App.tsx

Do you understand that if a reduced test case is not provided, we will intentionally delay triaging of your ticket?

• I understand

Which connector are you using (React/Angular/etc)?

React connector

Bug Description

When providing eventContent to the react <FullCalendar /> component, the function will be called many times over during event editing, crashing the calendar if the application is using a sub 18 version of react (ex. react 17 or react 16).

To reproduce:

1. open test case
2. open console
3. drag and drop an event
4. observed 10,000's of console logs and event calendar rendering bugs

This behavior is not present on react 18 applications.

Screen.Recording.2023-01-06.at.3.01.07.PM.mov

[arshaw]

queue for release fullcalendar/fullcalendar-react@4e439dd

[arshaw]

Released in v6.0.3

Updated repro:
https://codesandbox.io/s/fullcalendar-issue-forked-9q79h5?file=/src/App.tsx