Slider in Library Thumbnail Preview view

Can Anyone tell me what you’re supposed to do with the Library Thumbnail slider? It looks exactly like the Harmony Drawing replacement window yet it seems to do nothing. What’s it for?

Screenshot 2016-05-22 12.30.11.png

Since no one else knows either here’s the answer:
When you created a template out of a panel containing a layer motion, click the Play button or drag the slider to scrub through the panel.