code: def _sync_outlineexplorer_file_order(self):
          
          if self.outlineexplorer is not None:
              self.outlineexplorer.treewidget.set_editor_ids_order(
                  [finfo.editor.get_document_id() for finfo in self.data])
docs: Order the root file items of the outline explorer as in the tabbar
          of the current EditorStack.