fix popover problem with eventPositioned callback
fix popover problem with eventPositioned callback

fullcalendar/fullcalendar,arshaw/fullcalendar,arshaw/fullcalendar,arshaw/fullcalendar,fullcalendar/fullcalendar,oleg-babintsev/fullcalendar,oleg-babintsev/fullcalendar,arshaw/fullcalendar,fullcalendar/fullcalendar,fullcalendar/fullcalendar,oleg-babintsev/fullcalendar