I've tried the "Slideshow: Thumbnails" widget on mulitple occasions with varying options and can't get the Active State of the Thumbnails of this widget to work at all.
Am I doing something incorrect?? Is there a bug in the system?? When will this be corrected if it is a bug??
It looks like there is indeed a bug with active state thumbnails, thank you for reporting it. I've filed it and we will be addressing it for future versions.
As for an immediate workaround, you can use composition widgets instead of slideshows (though composition widgets are much more free-form, and the thumbnails will have to be arranged manually).