When the dateInput property is set to true, the readonly method does not make the widget completely non-editable. It restricts user input, however, the date can be modified using the arrow keys.

Reproduction of the issue in a Dojo sample:
https://dojo.telerik.com/OpIFacOz

1. Initialize DatePicker
2. Set the dateInput property to true
3. Call the readonly() method

Current behavior

Value can be changed with the arrow keys

Expected/desired behavior

The value should not be editable

Environment

• Kendo UI version: 2019.1.220
• jQuery version: 1.12.4
• Browser: [all]