By assigning the OnClientBeforeShow
property to a function you actually attach a handler for this event and you do not need to pass the function's arguments explicitly - they are automatically passed. This could not be the reason for the error you got.
I did not quite understand what you mean by "when i kept Mouse position at the bottom of the Aspx page it has to show the tooltip at the bottom of the Mouse position by scrolling the page down".
I think that the best way to proceed is that you open a new support ticket, prepare and send me a fully working, reproduction demo (including DB, if needed, e.g Northwind) along with a detailed explanation of the problem and the desired behavior and some screenshots. Once I receive this information, I will do my best to help.
the Telerik team
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