Please, note: Scrollbar of the form is hidden intentionally because of some technical and design issues. We don't have plans to put this in the box. Basically we believe there is no issue on that nowadays. You can scroll using mouse wheel on desktops or touchpad on laptops.
Anyways if you do want to have scrollbar we have a solution. First you need to remove CSS from ninja-contact-form.css
on line 124-126.
Then head to plugin's settings page in WordPess admin and add this custom CSS:
#ncf_sidebar .ncf_sidebar_cont_scrollable {
padding-right: 0px !important;
}
That's it!