Howdy,
I had the same problem – it appeared that new WP has set ‘position: relative;’ on #wpbody container and all absolute positioning on sortable elements are ruined (they are not created in main body node, but much more inside). So the quick, dirty and working solution for now is:
#wpbody {
position: static !important;
}
at the end of the /wp-content/plugins/nextgen-gallery/admin/css/nggadmin.css .
Hope this helps!
