If I add a new role with an inheritence of for instance "User" the addition of capabilities won't have any effect. For instance if I want to provide a user with the right to manage other users I won't get this option in Manager. I tested this with 4.3. Not sure if earlier version had the same behavior.
this is due to an issue in the Manager XML: the views in etc/apps/search/default.meta are defined in terms of groups and users, not capabilities. the manager XML has read access granted only to the admin role, and adding capabilities to other users does not give them those capabilities in the Manager UI. this isn't new in 4.3, btw.
there are plans to revamp this whole system in a future release, but it will take some time.