If you frequently modify security role and your wrist hurts because of all tiny mouse movements, there are some undocumented explicit links on the role dialog that could make your life much easier.
Clicking on the entity name (e.g. Account) will cycle all privileges for this entity (i.e. Create, Read, etc) through all access levels (i.e. none, user, business unit, etc).
Clicking on the privilege name (e.g. Create) will cycle this privilege through access levels for all listed entities.