message: Fix error root class for panel in knockout
diff: @@ -54,6 +54,7 @@ export class Panel extends PanelModel {
  koCss: any;
  koIsExpanded: any;
  koIsCollapsed: any;
  + koErrorClass: any;
  doExpand: any;
  constructor(name: string = "") {
  super(name);
  @@ -72,6 +73,10 @@ export class Panel extends PanelModel {
  this.doExpand = function() {
  self.changeExpanded();
  };
  + this.koErrorClass = ko.pureComputed(function() {
  + var rootClass = self.cssClasses.error.root;
  + return rootClass ? rootClass : "panel-error-root";
  + });
  }
  protected createRow(): QuestionRowModel {
  return new QuestionRow(this);
  