[Plugin: NextGEN Gallery] plugin causes ssl uauthenticated content error

I have enabled ssl on wp-admin and this plugin was causing the infamous “Contains unauthenticated content” warning. I used the httpfox extension and determined that the following url was generating the warning: https://www.mysite.com/wp-content/plugins/nextgen-gallery/admin/css/menu.css

https://www.ads-software.com/extend/plugins/nextgen-gallery/