No,
I edit the left menu of /projects in order to include the menu of /projects/web
And i don't know why but libresource failed ( libresource become unattainable even if i restart the database ).
although i tried with a fresh bootstrapped installation to first edit the left menu of /projects ( in order to include the menu of /projects/web ) and then create the ressource /projects/web. Then Libresource failed the same way.