the thumbnail stacks and tabs are great, but it would be even better to be able to group tours within them. This would allow grouping according to ground and 1st floor, interior or exterior shots, different sites, buildings etc or whatever you wanted to make navigation that little bit easier
I guess with either the stack or the tab it could work in one of two ways. First would be to maintain the current single click point to access the thumbs, but then once opened they could be grouped, maybe into separate rows or columns with a title. This would be my preference. The alternative would be to have the groups under separate stacks or tabs, so there are multiple tabs or stacks which can be opened independently, each of which would contain some grouping of thumbnails. Or did you mean in the PTP gui?