Bug report

While clicking tab key the button to choose Date or Time, Set and Cancel gets disappear

Reproduction of the problem

Dojo: https://dojo.telerik.com/eMaQIbAw

1. Click on the date button in the date time picker to open the Calendar popup

2. Press tab until the buttons disappear.

3. Pressing shift+tab will show the buttons again.


Expected/desired behavior
Set and Cancel buttons shall not disappear


Environment
Kendo UI version: [all]
jQuery version: x.y
Browser: [all]