mleder on "Wordpress 4.5 upgrade - admin area now a mess"

Here's the console output:

load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:9 JQMIGRATE: Migrate is installed, version 1.4.0
load-scripts.php?c=0&load[]=hoverIntent,common,admin-bar,wp-ajax-response,jquery-color,wp-lists,qui…:67 Uncaught ReferenceError: postBoxL10n is not defined
load-scripts.php?c=0&load[]=hoverIntent,common,admin-bar,wp-ajax-response,jquery-color,wp-lists,qui…:661 Uncaught TypeError: Cannot read property 'hasClass' of undefined(anonymous function) @ load-scripts.php?c=0&load[]=hoverIntent,common,admin-bar,wp-ajax-response,jquery-color,wp-lists,qui…:661n.event.dispatch @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:3r.handle @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:3n.event.trigger @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:3a.event.trigger @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:9(anonymous function) @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:3n.extend.each @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:2n.fn.n.each @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:2n.fn.extend.trigger @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:3(anonymous function) @ load-scripts.php?c=0&load[]=hoverIntent,common,admin-bar,wp-ajax-response,jquery-color,wp-lists,qui…:660i @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:2j.fireWith @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:2y @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:4c @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils&ver=4.4.2:4