How long have you had the problem? Did it happen immediately after the upgrade? Did it happen later on? Perhaps something got borked during the installation of the new files or maybe its even a plugin causing it. Have you tried deactivating plugins? Many of the plugins that ad an option page to the dashboard break the dashboard because of the redesign.
I had the same issue, it seems to be related to \wp-admin\admin-footer.php being incompatible with my theme. try changing the theme and see if that fixes it – for me as a very quick and dirty fix – i just deleted admin-footer.php, get an error, but i’m able to get the ‘submit’ buttons.