Comment 8 for bug 1483890

This is the three-level design Matthew suggested in #6. I'd personally favour to have this option. I believe the increase in complexity can be small if the selector will be well designed.
It could be a three-step selector, or two hierarchical switches. In any case, the naming must be very clear (suggestions see comments above). And the indicator should change its appearance in a way that makes the selected mode clear at a glance.