I am having a problem displaying the crayon popup in 2.4.1 (works in 2.3.1) in my code created custom post types. It displays in the edit post page fine.
My installation is complicated so I can't be sure although I tested various scenarios if there is a conflict.
But once I downgraded to 2.3.1 it worked no problem. 2.4.0 doesn't work.
Type Issue: 'undefined' is not an object (evaluating 'c.val').
My guess is there is a problem with fancybox introduced in 2.4.0