Uncaught TypeError: Cannot read property 'rowactions' of undefined in jqGrid for formatter:'action' - jqgrid

Question

I am using jqGrid V 4.6.0. and trying to implement grid with inline edit/delete functionality.I used formatter:'actions' for acheive this and also getting edit/delete icons in each row.But when i click on those icons i am getting following error in console :Uncaught TypeError: Cannot read property 'rowactions' of undefined and nothing happens in grid.same code and same example i've implemented before with jqGrid V4.4.4 and it worked well ,but in V4.6.0 i got this error.Please somebody help me.Thanks in advance :)
Code for reference:
jQuery("#theGrid").jqGrid({
url: '/Student/Grid',
datatype: "json",
colNames: ['Id', 'Firstname', 'Middlename', 'Lastname', 'Birthdate', 'Birthplace', 'State', 'Nationality', 'Religion', 'Ishandicaped ?', 'Actions'],
colModel: [
{ key: true, name: 'Id', sortable: true, resize: true, align: "center" },
{ key: false, name: 'FirstName', index: 'FirstName', editable: true, align: "center", editrules: { required: true } },
{ key: false, name: 'MiddleName', index: 'MiddleName', editable: true, align: "center", editrules: { required: true } },
{ key: false, name: 'LastName', index: 'LastName', editable: true, align: "center", editrules: { required: true } },
{
key: false, name: 'Birthdate', index: 'Birthdate', editable: true, align: "center", editrules: { required: true }, formatter: 'date', editoptions: {
dataInit: function (el) {
setTimeout(function () {
$(el).datepicker({
dateFormat: "dd-M-yy",
autoSize: true,
changeYear: true,
changeMonth: true,
showButtonPanel: true,
showWeek: true
});
}, 200);
}
}
},
{ key: false, name: 'Birthplace', index: 'Birthplace', editable: true, align: "center", editrules: { required: true } },
{ key: false, name: 'State', index: 'State', editable: true, align: "center", edittype: "select", editoptions: { value: "GJ:Gujarat;MH:Maharashtra;DL:Delhi;BNG:Banglore;RJ:Rajasthan" }, editrules: { required: true } },
{ key: false, name: 'Nationality', index: 'Nationality', editable: true, align: "center", editrules: { required: true } },
{ key: false, name: 'Religion', index: 'Religion', editable: true, align: "center", editrules: { required: true } },
{
key: false, name: 'IsHandicaped', index: 'IsHandicaped', editable: true, align: "center", edittype: "checkbox", editoptions: { value: "True:False" }, formatter: Demo1
},
{
key: false,
name: 'Actions',
index: 'tax',
width: 80,
align: "center",
formatter: 'actions',
formatoptions: {
delOptions: { url: '/Student/Delete' }
}
}
],
rowNum: 10,
rownumbers: true,
autowidth: true,
rowList: [5, 10, 20],
pager: '#gridPager',
viewrecords: true,
sortorder: "desc",
reloadAfterSubmit: true,
altclass: 'table table-bordered table-striped',
jsonReader: {
repeatitems: false
},
caption:'Studentdata JqGrid V4.4.4',
editurl: '/Student/Edit',
mtype: "post",
height: '100%',
hiddengrid: false,
serializeRowData: function (postData) {
debugger;
// new row id is "new_row"
postData.Id == "jqg1" ? postData.oper = "add" : postData.oper = "add";
return postData;
},
afterSubmit: function (response, postdata) {
if (response.responseText == "") {
$(this).jqGrid('setGridParam',
{ datatype: 'json' }).trigger('reloadGrid'); //Reloads the grid after Add
return [true, ''];
} else {
$(this).jqGrid('setGridParam',
{ datatype: 'json' }).trigger('reloadGrid'); //Reloads the grid after Add
return [false, response.responseText];
}
}
}
});