message: survey.getPanelByName returns PanelModel instead of IPanel
diff: @@ -31,7 +31,7 @@ import { SurveyTimerModel, ISurveyTimerText } from "./surveyTimerModel";
  import { Question } from "./question";
  import { QuestionSelectBase } from "./question_baseselect";
  import { ItemValue } from "./itemvalue";
  -import { PanelModelBase, QuestionRowModel } from "./panel";
  +import { PanelModelBase, PanelModel, QuestionRowModel } from "./panel";
  import {
  HtmlConditionItem,
  UrlConditionItem,
  @@ -4874,13 +4874,13 @@ export class SurveyModel extends SurveyElementCore
  public getPanelByName(
  name: string,
  caseInsensitive: boolean = false
  - ): IPanel {
  + ): PanelModel {
  var panels = this.getAllPanels();
  if (caseInsensitive) name = name.toLowerCase();
  for (var i: number = 0; i < panels.length; i++) {
  var panelName = panels[i].name;
  if (caseInsensitive) panelName = panelName.toLowerCase();
  - if (panelName == name) return panels[i];
  + if (panelName == name) return <PanelModel>panels[i];
  }
  return null;
  }
  