When you fill out a comment form for an entry, and you submit it but receive some error (say invalid email address format), when you click the link to get back to the form -- none of the data in the form is there.

Does anyone know how to set up the form so it remember the form inputs when you return from an error screen?

Offhand I think it is more a browser issue, what you might have to do is have some Javascript copy the text to the clipboard before submitting, though that may cause a security warning on some platforms / browsers.