Let's say you want to craft a sword that you have a diagram for. You talk to a Blacksmith and ask him to craft something. You highlight the sword and see that it calls for certain materials; using the base Griffin steel sword as an example, you need leather scraps, steel ingots, a monster brain and a monster eye. You already have the monster brain, so no worries there. You don't have leather straps or steel ingots, but they're highlighted in the crafting menu that you're looking at, which tells you that this blacksmith also sells them. You don't have a monster eye either, but it's not highlighted, which tells you this blacksmith doesn't sell that item and you'll need to get it elsewhere. You can also pin diagrams, which will cause highlights to show up in the shop menu anytime an item needed for a pinned recipe is being sold by a craftsman. This works for blacksmiths (weapons), armorers (armor), herbalists and alchemists (alchemy), along with the occasional shopkeeper selling alchemy supplies. The one thing that it still doesn't show you is what items you have in your inventory that can be dismantled to produce the ingredients you need, which comes up infrequently but can still be infuriating if you run around for 3 days looking for powdered monster tissue before realizing you could just dismantle some of your 8 million pounds of specter dust.