radical: i think that would just make it really confusing. I would probably just pull up another manufacture window for the item you want to see only those raw materials.

technically, even though you are still collapsing the tree, the manufacture still needs the same amount of raw materials.

also, it would be very hard to do what you are asking. the client would have to recalculate all the raw materials in the tree every time you click on a +/- making the page load lots more. basically, i don't think it's worth trying to implement :P