Lately I was working in an Application where I should change elements stackOrder inside a Spark panel. I try first to use getChildIndex, swapChildAt, etc, but was inmediatly confused by the compiler that says that the method should be called from a chiller of the caller. After some research, I discover that all element manipulation inside the spark panel should be done using element, so
addChild turns addElement
swapChildIndex turns swapChildElement
And so on.