weird, u have turn on blacksmith window ? Three was a bug, when u active sell button, sometime u sell Item, but i need have problem with changing weapons. When its happenes i mean situation? Maybe u can upload some video?
unfortunately, the the game didn't save when my laptop died (not sure if there ever was a save feature or anything. if there was, it didn't work for some reason ._.). but it might have had something to do with the blacksmith. but might i suggest making the selling click and drag to an area in the blacksmith window?