message: Monochrome should default to white not black.
  (TFS#903163)
diff: @@ -13,11 +13,14 @@ import { RenderSystem } from "./rendering";
  export abstract class DisplayStyleState extends ElementState {
  private _viewFlags: ViewFlags;
  private _background: ColorDef;
  + private _monochrome: ColorDef;
  constructor(props: ElementProps, iModel: IModelConnection) {
  super(props, iModel);
  this._viewFlags = ViewFlags.fromJSON(this.getStyle("viewflags"));
  this._background = ColorDef.fromJSON(this.getStyle("backgroundColor"));
  + const monoJson = this.getStyles()["monochromeColor"];
  + this._monochrome = undefined !== monoJson ? ColorDef.fromJSON(monoJson) : ColorDef.white.clone();
  }
  public equalState(other: DisplayStyleState): boolean {
  @@ -48,8 +51,8 @@ export abstract class DisplayStyleState extends ElementState {
  public get backgroundColor(): ColorDef { return this._background; }
  public set backgroundColor(val: ColorDef) { this._background = val; this.setStyle("backgroundColor", val); }
  - public getMonochromeColor(): ColorDef { return ColorDef.fromJSON(this.getStyle("monochromeColor")); }
  - public setMonochromeColor(val: ColorDef): void { this.setStyle("monochromeColor", val); }
  + public getMonochromeColor(): ColorDef { return this._monochrome; }
  + public setMonochromeColor(val: ColorDef): void { this._monochrome = val; this.setStyle("monochromeColor", val); }
  public is3d(): this is DisplayStyle3dState { return this instanceof DisplayStyle3dState; }
  }
  