We are trying to make time charts for some of our data. I've tried on several different datasets, all with multiple date/time fields, but on the X-Axis tab, where it says "Calculate interval between:", the date on the left is always blank, and the dropdown is empty. There are dates in the dropdown on the right. Am I missing something here? What do I have to do to get dates to show up in the left dropdown?

Thanks,
Jen