Ticket #51631: 51631.1.diff

src/wp-admin/css/nav-menus.css

@@ -777 +777 @@
         }
 }
 
+@media only screen and (min-width: 783px) {
+        @supports (position:sticky) {
+                #nav-menu-header {
+                        position: sticky;
+                        top: 32px;
+                        z-index: 1;
+                }
+
+                #save_menu_footer{
+                        display: none;
+                }
+        }
+}
+
 @media screen and (max-width: 782px) {
         body.nav-menus-php,
         body.wp-customizer {