Ticket #37589: 37589.diff

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

@@ -474 +474 @@
         background: #fff;
         -webkit-transition: background-color 0.15s;
         transition: background-color 0.15s;
+        /* Reset the value inherited from the base .accordion-section-title style. Ticket #37589. */
+        -webkit-user-select: auto;
+        -moz-user-select: auto;
+        -ms-user-select: auto;
+        user-select: auto;
 }
 
 #available-menu-items .open .accordion-section-title,