I am not sure if I am using this correctly so my problem may be my mis-understanding rather than a bug or larger problem.
I have a fullcalendar that gets initiated f
$('#calendar').fullCalendar('removeEvents');
$('#calendar').fullCalendar('addEventSource', 'JsonResponse.ashx?technicans=' + technicians);
$('#calendar').fullCalendar('rerenderEvents');
The above solution works, but every time you run it, it add an eventSource.
So when you need to run $('#calendar').fullCalendar('refetchEvents'); you will get events from all sources, so many dublicate events and events from all previous sources.
The solution that works for me good is:
$('#calendar').fullCalendar('removeEventSource', 'JsonResponse.ashx?technicans=' + technicians);
technicians = new_technicians_value;
$('#calendar').fullCalendar('addEventSource', 'JsonResponse.ashx?technicans=' + technicians);
And there is no need for "rerenderEvents" or "refetchEvents".
After "addEventSource" events will be immediately fetched from the new source.
After that "refetchEvents" will work as supposed to when needed.