Thank you for contacting us.
Could you please give us more information which version of RadControls you are upgrading? Also, with which Skin exactly you are facing issues?
Addition, about the JS error, I am afraid I am not able to identify what's causing the problems you are facing based on this information. I would appreciate it, if you could isolate the problem in a simple running project so that I can debug/examine it locally.
Looking forward to your reply.
the Telerik team
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