Thank you for writing.
The reason for the observed exception is that we are using the properties of the Text property to handle the text selection in the control. I will log this case and we will handle it in a future release. Here is a link to the item: http://feedback.telerik.com/Project/154/Feedback/Details/129142
I have updated your Telerik Points
for this report.
For the time being, you should use the method you found, or just set the Text to string.Empty
(this is what the method does internally as well),
instead of using null.
I hope that you find this information useful.
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