Thanks for reporting this.
It is a known issue. At this moment you can remove items
one by one as we have problem with the clear()
method. You can track the status of this issue here
Please accept our apologies for the caused inconvenience.
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? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items