Hasan Schiers N0AN

I've been playing with DXView's Sunrise/Sunset table which is wonderful for looking at potential 160m openings (and 80/40) and I saw the choice available for Grayline...but every time I choose it, after having input a callsign that shows Sunrise/Sunset, the list of SR/SS goes away (as it should) but the Grayline is blank.

How do I make use of the Grayline feature in non-realtime? 
(or even real time for that matter)
73, N0AN

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