Pop Up Style Question

Hi, I am using your PopUp plugin on my site, http://www.yourmusicvault.com and its working great. But is there an option to grey out the background when the popup is executed?

I don't mean the background within the popup window itself (I can see that option in the plugin settings), I mean basically everything else on the screen apart from the popup window. I have attached a screenshot....

Thanks!

James.