In terms of the calendar box, I tried jasonvr's example.

It works if I do not add any filters to the search. Now, it comes up as Dec 23/25 for economy class only.

The filter does not allow you to enter a specific airline - otherwise the functionality of alternate dates does now work.

What jasonvr's and my example does not display, is the airline that these awards on the other dates are available.

I also tried to filter this functionality by class - I added the letter "c" to the class requested - nothing happens.