Ticket #26630: 26630.8.patch

src/wp-admin/includes/plugin.php

@@ -991 +991 @@
                 add_action( $hookname, $function );
 
         if ( empty($icon_url) ) {
-                $icon_url = 'none';
+                $icon_url = 'dashicons-admin-generic';
                 $icon_class = 'menu-icon-generic ';
         } else {
                 $icon_url = set_url_scheme( $icon_url );