Not possible to select a date range on the activities tab. When clicking in the date range entry box, calendar is shown. After selecting a date all I get is an error message saying the date format is incorrect.
Weird. Just tried it again to get a screen capture, but it works now! I was selecting using the calendar, just like in your screenshot. After selecting a date in the calendar, it entered Nan/Nan/Nan, instead of the actual selected date.
On a side note, it would be nice to have the filters available when selecting ALL activities. And that the CSV export function would actually export all filtered activities without having to recall them all first in the browser window.