In the demo (http://demos.telerik.com/kendo-ui/editor/immutable-elements) or the preview in the api reference (http://docs.telerik.com/kendo-ui/api/javascript/ui/editor#configuration-immutables) the immutable elements (html elements that have the contenteditable="false" attribute) can be deleted.
They can be selected by double clicking and deleted by pressing Delete. Or just selecting everything in the editor and pressing Delete. Tested with Chrome 53 and Internet Explorer 11.
I am confused as the description for Immutable Elements states:
"The Kendo UI Editor widget and its Immutable Elements feature enables you to predefine elements in the content area that cannot be edited by the end user."
I assumed that edited also meant deleted. Is this the intended behaviour?