Extra capability problems

What exactly are you trying to achieve: do you want to restrict access or allow access, and for which roles/users?

In general, the “extra capability” field acts as a filter that’s applied on top of other permissions. To be able to see a menu item, the user must first meet all of the other requirements (e.g. having the required capability, role permissions in the Pro version, etc). Users that pass those checks and have the extra capability will be allowed access.

For example, lets say you have a menu item where the default required capability is manage_options. If you set the extra capability to “shop_manager”, only users who have both the manage_options capability and the Shop Manager role will be able to access this menu. Users who only have the Shop Manager role (but not the required capability) won’t have access.

That’s probably the reason why “shop manager + administrator” didn’t work. It allows only users who have both roles: Administrator and Shop Manager. A user that has only one of those roles – like Shop Manager – won’t see the menu.

Unfortunately, that’s not possible with the free version of this plugin. One of the limitations of the free version is that you can’t give a role access to a menu; you can only prevent/restrict access. You would need either the Pro version or a different role editing plugin to give Shop Manager access to something.

aha i see is for sure that pro will work?

It’ll probably work, but it’s impossible to guarantee that without actually testing it. (If it doesn’t work, I would of course give you a refund.)

what about if the restriction is hard­coded in the plugin?

In that case, the only thing that will work is editing plugin source code. It’s usually not possible to override restrictions like that with Admin Menu Editor Pro or any similar plugins.