A conflicting item would be Iron Greatsword and Copper Greatsword
Not Iron Pick and Iron 2h axe
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Line of Sight doesn't necessarily mean sight, nor do they really need sight... its like.. a box. there's a box of like "consideration" and a box of like "reach"
Like. you can set fully assembled items in the shelves on the front counter, like, behind the counter kinda way, the customer "can't see them" but they can grab them if nothing else goes wrong.
But they can't grab them if they're on the Greatsword display wall/shelving - but they can "see" them from there -because in 0.0.81 I had experience with having to fumble through items over there to find "the one"
But but. in 0.0.82 I've had moments where there was say - an iron 1h sword, and a tin 1h sword - both under the front counter, where they've sold from before - just without the - - - anyway. when I would pull the item back and toss it to the door in the back, across from workbench - they'd immediately notice the correct item. (provided nothing else went wrong, that it was the closer item)
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You dismantle things by taking them back to the anvil and then striking them with a hammer.
You don't have to accurately get them on the anvil - Just get about to the steps, and you can toss it at the anvil - with the cursor over the anvil.
If it was tossed like that, or if any part is actively touching the anvil, the smack will cause the parts to separate
*pardon this entire response if it sound like utter gibberish - there's reasons if it does, but even those would likely make no sense.