Poster frame selector does nothing

In the documentation is simply says click on a chapter button, the Lolllipop will appear, move that left or right in the timeline and you see a preview of the frame at it's location. Nothing happens. When I move the lollipop nothing changes in the viewer.

I don't know if this is related, but when I create the Video and Audio TS folders using the File/Share/DVD option and I play them in DVD Player there are no thumbnails shown next to the Chapter Button labels.

Thanks,

Pete D.