"Disable on mobile browsers" not working

Hi,

I have this option checked but the modal popup is still showing up on mobile browsers. The website is:

http://www.dresshits.com

Could it be because the Mobile_Detect.php seems to be inactive? I’m not sure what that means but when I go to edit the plugin and select the file, is shows this as title:

Editing modal-dialog/Mobile_Detect.php (inactive)

http://wordpress.org/extend/plugins/modal-dialog/