Quick summary

If there's a menu created through the customizer it will appear on FSE under the menu selection option as a classic menu. If the menu is selected, a duplicate is created under the new menus. Each time it's selected a new detached menu will be created usually causing confused users to end up with several copies of that menu.

This causes customers that are used to the customizer to reselect the menu (and therefore create a new detached copy) to update the changes they do on the customizer within their site in the site editor.

Steps to reproduce

Create a menu on the customizer.
Go to FSE, go on a created menu (or create a new one) and on the toolbar, click on "select menu" and select the classic menu. If we check again the tool bar under "select menu" we will see a new menu created.

What you expected to happen

Ideally, on FSE themes, the customizer menu area should give a warning that those changes have to be done directly on the site editor from now on. Since the customer can have previous menus, and leaving the adaptation to the customer doesn't seem to be feasible without creating the duplicates, could those be created automatically once a FSE theme is switched on? Those duplicates could be called xyz-copy or something like that)

Accessing Customizer\menus could display only a warning telling the user that menu changes will have to be done through the site editor directly and those previous menus were copied with the xyz-copy names.

What actually happened

Customizer\menu still allows to create and edit menus, whose changes are not reflected on the site editor. So most customers can try selecting the classic menu after a change to have it appear on the site editor resulting on a duplicate at each change.

Context

No response

Simple, Atomic or both?

Simple, Atomic

Theme-specific issue?

FSE themes (Zoologist was used)

Browser, operating system and other notes

Chrome Version 101.0.4951.54 (Official Build) (x86_64)
MacOs monterrey 12.3.1

Reproducibility

Consistent

Severity

Most (> 50%)

Available workarounds?

No but the platform is still usable

Workaround details

The additional menus can be deleted by accessing Manage menus (under the nav-menu toolbox from the site editor)