z-index property specifies the stack order of an element. An element with greater stack order is always in front of an element with a lower stack order.z-index and order of elements by dragging them by the handle (see picture below). In this case you are changing z-index and also the order of option sets.z-index correctly? You can set z-index manually (see image below). In this case you need to set frames z-index to 3 and wheels and tires z-index to 2.