sortable.showIndexes Boolean (default: true)

If set to true the user will see sort sequence indicators for sorted columns.

Example - do not allow unsorting

<div id="grid"></div>
<script>
$("#grid").kendoGrid({
  columns: [
    { field: "name" },
    { field: "age" }
  ],
  dataSource: [
    { name: "Jane Doe", age: 30 },
    { name: "John Doe", age: 33 }
  ],
  sortable: {
    showIndexes: true,
    mode: "multiple"
  }
});
</script>