Thank you for bringing our attention to this issue. This is a known bug and its status currently is in progress, It is also available in PITS on this public URL
where you can track its status. Please excuse us for the inconvenience.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items