Toolbar, plain code toggling, etc. not working

I have been using Crayon for almost a year now, and it has worked excellently — thank you. Recently though, the toolbar buttons and plain code toggling (via double-click) has broken. I’ve only just noticed, so I’m not sure when they broke, though it’s probably within the last couple months. They’re also broken in the default WordPress themes (Twenty Ten & Twenty Twelve). I don’t have any jQuery in my theme.

Link to an example page.

P.S. Highlighting for R is often kind of strange, especially for variable names.

https://www.ads-software.com/extend/plugins/crayon-syntax-highlighter/