Don't know if this has been addressed or not, but there seems to be a glitch when you are trying to navigate from the beginning of a slideshow to the end.  If the "next/previous row" nav button next to the thumbnails is pushed too fast, the animation jumps, and at the end of the gallery it overshoots beyond the last frame of thumbnails.  Everything just turns white; no thumbnails display.  It seems that the nav button doesn't disappear until the animation of the moving thumbnails completes, as opposed to after clicked.