public HighlightLayer(LayeredHighlight layers, Color color)
 {
     this.layerBelow = this;
     this.layerAbove = this;
     this.Color      = color;
     this.layers     = layers;
     this.disposed   = false;
 }
 public HighlightLayer(
     LayeredHighlight layers,
     HighlightLayer layerBelow,
     Color color)
     : this(layers, color)
 {
     this.layerBelow            = layerBelow;
     this.layerAbove            = layerBelow.layerAbove;
     this.layerBelow.layerAbove = this;
     this.layerAbove.layerBelow = this;
     this.layers.UpdateRendererColor();
 }