P: Show stacks as open during Auto-Stacking

The ai auto stacking shows the stacks closed so you can't see if it's stacked the photos correctly and then if it hasn't you have to keep opening the the auto stack slider to try guess if it's done a good job . I think it would be better if it showed the stacks open with the first photo of each stack being highlighted then you can see which photos are being put where as you move the slider.