Resolved surveyjs/private-tasks#469 - v2.0 - Advanced/Basic Header Considerations + Breaking Changes (#6634)

Co-authored-by: tsv2013 <tsv2013@noreply.github.com>

Author: tsv2013

packages/survey-creator-core/src/creator-base.ts

@@ -2112,6 +2112,9 @@ export class SurveyCreatorModel extends Base
    * @returns true if initial survey doesn't have any elements or properties
    */
   protected initSurveyWithJSON(json: any, clearState: boolean): void {
+    if (!json) {
+      json = { "headerView": "advanced" };
+    }
     this.existingPages = {};
     const survey = this.createSurvey({}, "designer", undefined, (survey: SurveyModel) => {
       survey.skeletonHeight = 188;