Hi Samir Vaidya,
Can you try and drop a control and edit it and then attach the trace log
and send it to me so I can have a closer look at the service exceptions ( if the system caught any ). After you send me the tracelog I will analyze it and report back to you my findings. Also can you check the following KB.
All the best,
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