An Effect Layer adds a style effect (for instance, a glare effect) to the linear gauge.
When a new effect layer is added to the gauge, it is painted foreground all other elements because its BaseLeafPrimitive.ZOrder property is set to -1000 by default.
To bring this layer behind other gauge elements, you need to set the ZOrder property to a higher value.
An effect layer is represented by the LinearScaleEffectLayer class.
The table below lists the main properties affecting element behavior and appearance.