I just replied to your support ticket on the subject. For your convenience I have pasted below my answer:
By default, the RadSpell's dialog is loaded centered on the page and
you should not experience this problem. Are you running your page in
quirksmode? Could you please, make sure that your page DOCTYPE is XHTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
If this doctype does not solve the problem, can you please, send us a
sample working project that demonstrates the bug? We will examine it
and try to provide a solution after that.
Thank you for your cooperation.
All the best,
the Telerik team
Check out Telerik Trainer
, the state of the art learning tool for Telerik products.