We've created a simple English site with a few pages for development. We are using the latest version, Sitefinity 5.1.3270.0 PE.
The site is going to be bilingual, and I'm trying to add a French version of the content. I start by going to Administration -> Settings -> Languages and adding the French language. Everything works and I save.
When I visit the Pages tab, there is now the extra column for different language versions, with French grayed out. I click the FR icon to create a french version of the page.
The error seems to be coming from this line:
The error reads:
FF: TypeError: firstItem.prop is not a function
IE9: Object doesn't support property or method 'prop'
Chrome: Uncaught TypeError: Object #<Object> has no method 'prop'