The "Add Location" button in "Location" tab of admin ui will be greyed out for an editor if that editor does not have the right to create a content of the viewed content type without any limitations.

If a user has the right to create a content of a certain content type limited to some parent content type the button will be greyed out, although it should be selectable, because the user does have sufficient rights to add a locaiton to the existing content.

Removing the Content Type of Parent limitation from the user's Content/Create permission will make the button selectable again, but this is obviously not what we want.

Steps to reproduce:
1. Create a new user group and name it "testGroup".
2. Create a new user "testUser" inside this group.
3. Create a new role "testRole" and assign it to the "testGroup" user group without any limitation.
4. In the role "testRole", configure policies like in the attached screenshot.
5. Log into the back office as "testUser".
6. Go to the user subtree and try to add a new location for a user group and for a user.

Result:
For the user group, button is enabled but disabled for users.

Note1: in v1 such operation isn't possible both for user group and user.
Note2: changing limitation for Manage_locations to User and User group enables the button.