fullcalendar - Full calendar event rendering happens only for particular week -

i using fullcalendar plugin display data 1 week. problem event rendering week select first. later when change week events getting created not rendering. when change again week selected first, event creation , rendering both happens. using $('#calendar').fullcalendar('gotodate', weekstartdate) go desired week.

    $.ajax({         type: "post",         contenttype: "application/json",         data: '{}',         url: 'dataservice.svc/cmstrandselection',         datatype: "json",         async: false,          success: function (data) {             $('#calendar').fullcalendar({                 header: {                     left: '',                     center: '',                     right: '',                     height: 300                 },                 defaultview: 'basicweek',                 editable: true,                 columnformat: 'dd dddd',                 events:                     $.map(data.d, function (item, i) {                         debugger;                         var event = new object();                         event.id = item.eventid;                          event.start = item.start;                         event.end = item.endd;                         event.title = item.title                         event.color = 'white';                         event.allday = true; //                              return event;                     }),                 eventrender: function (event, element) {                     //some code                     });                 }             });              $('#calendar').fullcalendar('option', 'height', 400);         }     });