Ryan Stutzman on "[Plugin: Country Specific Menu Items] Update stopped working"

Hi, I have not found this problem so here goes. When I activate Country Specific Menu Items plugin the Preview and Update buttons on the WP page editor stop working. When I de-activate the plugin Preview & Update start working again.

https://wordpress.org/plugins/location-specific-menu-items-by-country/

I am using the Twentytwelve theme.

Well that's no good. What version of WP are you using?