The TinyMCE was updated to v4.0 with WP 3.9 so a lot has changed, I wrote up a small tutorial for developers looking to update their themes and plugins to provide support for the new editor, hope it’s useful to you!http://www.wpexplorer.com/wordpress-tinymce-tweaks/
Nice one, WPExplorer!
Whilst I’ve already scrambled to fix some bits ‘n’ bobs after the 3.9 release – this is a very comprehensive write-up. I wasn’t even aware of the Popup feature of TinyMCE – thank you for sharing this with us!
Thank you very much WPExplorer!