Hi Yang,
You can manipulate the selections's range via the exposed methods in the API--
http://www.telerik.com/help/aspnet-ajax/editor-getrange.html.
As for manipulating the selection, it is a browser functionality and you can read more about it in this MDN help article--
https://developer.mozilla.org/en-US/docs/Web/API/Range.
Regards,
Ianko
Telerik
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