unfortunately copper readily oxidizes in atmosphere to form carbonates (green), by touching would form sulfides (black). in general copper compounds can leach through the skin and are toxic (although in large amounts) to humans too, not just to bacteria and other microbes. brass however might be safer for long term touch. i actually saw quite a few brass handles in old buildings' doors in europe
for me it's linked dropdowns (you select something from dropdown A, dropdown items from B change and so on)