<telerik:RadSpreadsheet runat="server" ID="RadSpreadsheet1">
</telerik:RadSpreadsheet>
<script type="text/javascript">
    (function () {
        var kendo = window.$telerik && window.$telerik._kendo;

        if (!kendo ||
            !kendo.spreadsheet ||
            !kendo.spreadsheet.ContextMenu) {
            return;
        }

        var contextMenu = kendo.spreadsheet.ContextMenu;

        if (!contextMenu.fn || contextMenu.fn._radSpreadsheetContextMenuPatched) {
            return;
        }

        var commandsDictionary = {
            CommandCut: 'cut',
            CommandCopy: 'copy',
            CommandPaste: 'paste',
            CommandHideRow: 'hide-row',
            CommandUnhideRow: 'unhide-row',
            CommandHideColumn: 'hide-column',
            CommandUnhideColumn: 'unhide-column',
            CommandDeleteRow: 'delete-row',
            CommandDeleteColumn: 'delete-column'
        };

        contextMenu.fn._onItemClick = function (sender, eventArgs) {
            var item = eventArgs.get_item();
            var element = item.get_element();
            var action = commandsDictionary[item.get_value()];

            kendo.jQuery(element).data('action', action);

            this.trigger('select', {
                item: element
            });
        };

        contextMenu.fn._radSpreadsheetContextMenuPatched = true;
    })();
</script>