message: scrollableSelector can be undefined, add a check
diff: @@ -1872,8 +1872,9 @@ export class Question extends SurveyElement
  this.destroyResizeObserver();
  if(!!el && this.isDefaultRendering()) {
  const scrollableSelector = this.getObservedElementSelector();
  + if(!scrollableSelector) return;
  const defaultRootEl = el.querySelector(scrollableSelector);
  - if(!!defaultRootEl) {
  + if(!defaultRootEl) return;
  let isProcessed = false;
  let requiredWidth: number = undefined;
  this.resizeObserver = new ResizeObserver(() => {
  @@ -1896,7 +1897,6 @@ export class Question extends SurveyElement
  this.resizeObserver.observe(el);
  }
  }
  - }
  protected getCompactRenderAs(): string {
  return "default";
  }
  