Hello,

I've noticed that any attempt at calling `dataSource.read()` on a datasource attached to a Kendo Menu results in keyboard accessibility breaking.

Steps to reproduce:

1. Use this code as a starter: https://dojo.telerik.com/IJOyUzEX/2

2. Notice that tabbing to the menu works the first time 

3. Activate the menu and close it.

4. Now try to tab into the menu again. It does no longer work.

Are there any better methods to have Kendo Menu dynamically generate the list everytime an open event is triggered?