Well thats only useful for that single recipe - considering how many there are, unless you specifically need to get that single one completed, it seems a tacked on feature that isnt that useful.
It would have been more useful to do a pop up box against each item that can be bought when you highlight it so you can see what its used in and the amounts needed.
EDIT: Just realised I just said the same thing previously, what I mean is say you highlight the plant blowball to buy and it told you what x,y,z recipe/crafting item it could be used on and how many for each you need. If that amounts to say 30 of them then it seems worth keeping 30 while you sell off the rest. If you have things that serve no purpose then you could happily know you can sell them without checking everything manually. Far better than what theyve given now because if you are desperate to finish a recipe/crafting item you are likely to know what ingredients to look out for - having it pinned isnt that useful other than filling that dead space on the right hand side.
ps3ud0