Here’s what Safari error console says for the newsletter editor:
“[Error] TypeError: ‘undefined’ is not an object (evaluating ‘_.memoize’)
(anonyme Funktion) (load-scripts.php, line 31)
[Error] ReferenceError: Can’t find variable: Backbone
(anonyme Funktion) (notes-common-v2.js, line 32)
[Error] TypeError: ‘undefined’ is not an object (evaluating ‘_.extend’)
global code (admin-bar-v2.js, line 2)
[Error] TypeError: ‘undefined’ is not a function (evaluating ‘$(‘.wp-review-color’).wpColorPicker()’)
(anonyme Funktion) (admin.js, line 155)
c (load-scripts.php, line 3)
fireWith (load-scripts.php, line 3)
ready (load-scripts.php, line 3)
q (load-scripts.php, line 3)
[Error] TypeError: ‘undefined’ is not a function (evaluating ‘element.dispatchEvent(event)’)
fire (prototype.js, line 5733)
_methodized (prototype.js, line 417)
fireContentLoadedEvent (prototype.js, line 5819)”