The Kendo UI NumericTextBox does not support loading animation out of the box.
I can suggest using the progress
method of the Kendo UI widget to set the loading animation for the widget. Please have in mind that a custom CSS rules will be required in order to modify the loading animation position:
I made a Dojo example demonstrating this implementation:
I hope this will help to achiеve the desired result.
Telerik by Progress