On the content type edit form, under 'Comment settings', the number before 'comments per page' is invalid/undefined

Fixed number of comments per page in "Comment settings" content type edit form. Needs Review.

1) Coding style issues, check your patch in the browser, i can see tabs instead of actual spaces in the indentation. The new function's doxygen also does not follow codying style standards.
2) There is a comment stating "Set "Comments per page" setting to textfield so it allows more gradual control over the number of comments to show." and now you are undoing that. I am not sure that is the right approach.

I agree with @nagba.

Here's a solution that corrects the javascript selectors in the fieldset summaries. It also includes a small code standards correction.

Patch #3 works for me