Chrome Surprise: "Prevent this page from creating additional dialogs" Not Taking Effect

Some annoying web pages, upon being exited, produce dialog boxes begging you to not leave. Somehow, the pages manage to produce yet another, similar dialog after you choose to indeed leave. Chrome, fortunately, has a checkbox called "Prevent this page from creating additional dialogs" designed to combat such behavior.

Interestingly, though, checking that box and then pressing the X in the upper-right of the JavaScript dialog seems to cancel the entire closing action. The checkbox, if the page produces another dialog, is still unchecked. That's understandable, given that the user chose to remove the entire dialog and not save what was in it. I do wish, however, that the checkbox's state would be saved, as I believe it would lessen the confusion of panicked novice users.