I am sending you a working implementation of this drag-and-drop approach. Please compare your code to that in the project to see if you can find any differences that might lead you to the cause of the issue.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items