Hi Rikard
I have found the soltion in the forum,
Many thanks to Yigit :

Need to add the following line in the wp-config.php file near top

define(‘CONCATENATE_SCRIPTS’, false );

No it works perfect

https://kriesi.at/support/topic/problem-with-menu-drag-and-drop/

Rgds
Nicolas

Many thank for your help I copy and past the code, but the effect doesn’t work on the scroll .
It works when I refresh the page on the inconbox.

Rgds