Thank you for writing.
I have tested this case and it seems that once the editor is cleared, the cell Value remains null. Please refer to the attached video.
Still, if I have missed your case you can use the CellEndEdit event, where you can change the cell value, after the user finishes the edit process.
I hope that you find this information useful. Should you have any other questions, do not hesitate to contact us.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.