Currently, widget does not support such functionality. You can, however, return the items that are "read-only" manually. Check this Dojo demo
for one possible approach. You will need to hide the "X" button manually too - find the LI elements
and hide the <span> element to all tags that should be "read-only".
Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI