message: BF: TFS#895111: addWhiteOnWhiteReversal sets bgColor alpha to 0, thinking it's a copy.  This enable blending with background HTML canvas (results in weird behavior too).  Fix: addWhiteOnWhiteReversal must operate on clone.
diff: @@ -20,7 +20,7 @@ export function addWindowToTexCoords(frag: FragmentShaderBuilder) {
  export function addWhiteOnWhiteReversal(frag: FragmentShaderBuilder) {
  frag.addUniform("u_reverseWhiteOnWhite", VariableType.Float, (prog) => {
  prog.addGraphicUniform("u_reverseWhiteOnWhite", (uniform, params) => {
  - const bgColor: ColorDef = params.target.bgColor;
  + const bgColor: ColorDef = params.target.bgColor.clone();
  bgColor.setAlpha(0);
  const doReversal = (bgColor.equals(ColorDef.white) && params.geometry.wantWoWReversal(params)) ? 1.0 : 0.0;
  uniform.setUniform1f(doReversal);
  