Been struggling with this for days. I'm using a rounded rectangle as a custom slider track. For the custom highlight track skin, I'm using a regular rectangle with a gradient fill. I want to mask the regular rectangle to stay within the bounds of the rounded rectangle. Problem is, how do I get a reference to the instance of the slider's 'track' object so that I can set it as the mask for the highlight track? Is what I'm trying to do even possible? If I use a rounded rectangle for the highlight track, it starts as a circle when you first start dragging the slider, so it doesn't fill the first segment of the track until you pass the first snap interval.