Not sure if this is a bug or not, but: If you load up all of the seat inventories of the Hitch-hiker Storage container for example, but there is no Kerbal in the seat, you cannot access the inventory of that seat. Is that a feature or a bug? I just imagined you would be able to right click and 'access inventory of seat 0' or something. EDIT: To clarify, you fill the inventory in VAB, but then can't access it after launch.