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Permissions-resource interaction
The ability to perform actions related to resources depends on To assign resources to roles, you need the Manage version of the Roles permission. The View version will allow you to see only those resources already assigned, and without this permission at all you will not see the option in the Navigation pane.
The process of assigning resources is determined by this combination of permissions and resources:
Assigning permissions a resource permission without assigning resources will only grant theoretical abilities with no actual resource to work with (see Role permissions to know more about the actions each level involve).
Assigning only resources without permissions is not allowed (the tab will be disabled unless you have at least the view level of the corresponding permission).
The permission level determines the maximum scope of action for the resource. For example, if you set the permissions to view, you cannot assign the resource to manage. However, if you set the permissions to manage, you can choose that a specific resource is set to view.
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