It seems that no matter what I change the Opacity value to in the plugin settings, the overlay (#cboxOverlay) is always 0.9 opacity. I couldn't find any other topic with this trouble, so I'm not sure if this is a result of the latest update or if there's something wonky in my WP setup. (I just started using this plugin, so I can't say if this was a previously existing issue or not.)
A live example is here when you click the "Sign Up" button in the blue box. The settings specify an opacity level of 0.3, but apparently that communication is breaking down somewhere.