message: Add isDisplayMode function into expression
diff: @@ -105,3 +105,8 @@ function isContainerReady(params: any[]): any {
  return true;
  }
  FunctionFactory.Instance.register("isContainerReady", isContainerReady);
  +
  +function isDisplayMode() {
  + return this.survey && this.survey.isDisplayMode;
  + }
  + FunctionFactory.Instance.register("isDisplayMode", isDisplayMode);
  