When Gravity queues scripts or styles for loading on the frontend and admin side it is doing so using the wrong protocol, so the end result is loading http:// resources on a secure page, giving the user warnings.
I checked that you're using
plugins_url() to determine the plugin's path, so I'm not really sure why it's not being respected. The most likely cause is that my SSL plugin is firing after Gravity. Do you guys have any experience with that being the case with the WordPress HTTPS plugin?http://wordpress.org/extend/plugins/wordpress-https/