It was working in the playground but not the app. As I thought I had used the code incorrectly :). With some work I got it to function in the app too. Here is how it looks now:         let button = UIButton()         button.addTarget(self, action: #selector(self.selectTack(sender:)), for: .touchUpInside)             let filteredProducts = products.filter { $0.item.contains(key)}             for product in filteredProducts {                 if let itemPosition = product.item.firstIndex(of: key) {                     let foundColor = product.colorName[itemPosition]                     if value > 0 {                     button.setTitle("\(foundColor) \(product.brand) \(product.category), amount: \(value)", for: UIControl.State.normal)                     tackStack.addArrangedSubview(button)                 }             }         }     }