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This might be a personal preference, but I think it should be a general solution.
When there is an error in the CTools modal, I believe the modal should scroll back to the top, so the error message is visible to users.
What's weird though, is that on a form submit, the modal will jump a slight amount (20px) up the page. If the intended behaviour is to scroll to the top, then this is a bug report for Chrome. :)