Kendo grid duplicate records inserted

I haven't seen this problem in my code. I do however have a "complete" event handler on my create and update events that refreshed the grid - it may help you:

  dataSource: {

    type: "jsonp",
    transport: {
        read: UrlBase + "getAll",
        update: {
            url: UrlBase + "Update",
            dataType: "jsonp",
            complete: function (e) {
                $("#grid").data("kendoGrid").dataSource.read();

            }
        },
        create: {
            url: UrlBase + "create",
            dataType: "jsonp",
            complete: function (e) {
                $("#grid").data("kendoGrid").dataSource.read();
            }
        },
        destroy: {
            url: UrlBase + "destroy",
            dataType: "jsonp",
            complete: function (e) {
                $("#grid").data("kendoGrid").dataSource.read();
            }
        }
    },
   ...

You should define a custom command in your toolbar as:

toolbar   : [
    {
        name : "my-create",
        text : "Add new record"
    }
],

Then, add an event listener to it, using as selector k-grid- plus the name of the command.

$(".k-grid-my-create", grid.element).on("click", function (e) {
}

Finally we will use the ability of Kendo UI datasource for inserting in a specific point:

var dataSource = grid.dataSource;
var total = dataSource.data().length;
dataSource.insert(total, {});
dataSource.page(dataSource.totalPages());
grid.editRow(grid.tbody.children().last());

Please, realize that we should move to the last page after inserting the row. This should be ok with having columns sorted by date.

Please, check the code here: http://jsfiddle.net/OnaBai/sAVGk/