Allow arrays in the URL params of the iFrame Source &cars=chevy&cars=ford
Right now using arrays in the URL params breaks the iFrame. The plugin removes the  from the URL.
Actually Wordpress does remove them when parsing shortcode attributes. They never reach the plugin.
I have a solution for this implemented: You need to use the BBCCode style of the pro version.
http://www.tinywebgallery.com/blog/advanced-iframe/advanced-iframe-faq -> How to use urls with special characters like 
Best regards, Michael