I have disabled access to content for anonymous users by unchecking "View all content". This also made the main menu disappear, which is good. To re-enable the menu I had to make both "Menu" and "Menu Widget"
to be able to set Role permissions for the Anonymous user.
The problem is that when you remove the "Creatable" flag, the Role permissions seem to be gone too (in other words, access to the menu is prohibited for anonymous users again).
Is it by-design that the Creatable flag for a Content Item is related to the Role permissions feature?
I was under the impression that the "Creatable" flag is just providing a link in the "New" menu as stated here: