I've just upgraded my WordPress site from 4.3.1 to 4.4, and I've just come across an issue which I've tested, and it does seem to happen upon upgrading the core from 4.3.1 to 4.4.
When I go into a post or page with a WYSIWYG editor, I cannot switch tabs between 'Visual' and 'Text'. Whatever the tab was before the upgrade, it's stuck on.
Anyone else had this issue?
(I think quite a few styles and scripts are loaded through the header.php so I'm going to move these to the functions.php file, registering them and enqueing them so I can load them only when not in the admin area.)
Uncaught TypeError: Cannot set property 'toolbar1' of undefined