Customising Comment Submission Error Page

Hope this isn’t a stupid question 😉

When I submit a comment and leave off a required field, I get taken to an empty page that simply says “Error: please fill the required fields (name, email).”

Is this normal behaviour, to not have it styled as per the theme? I guess it saves on bandwidth, but is there a simple way to apply my theme without having to edit wp-comments-post.php (which gives me another thing to do with every upgrade?).

I guess I could do some javascript validation as well, but just thought maybe there was a simple answer. 🙂

Cheers,

Ross