When validation fails while posting a comment (e.g. when comment length > 1000) a TemplateDoesNotExist exception is thrown. When validation fails the _preview function from threadedcomments is called. This function renders a response with threadedcomments/preview_comment.html template.
This problem happens also when an empty comment is posted.
It does not happen here, so apparently this site has a preview_comment.html template. But I can't find it in github.
