def update(self):
        """Once you open a dataset, it activates all the widgets.
        """
        self.info.display_dataset()
        self.overview.update()
        self.labels.update(labels=self.info.dataset.header['chan_name'])
        self.channels.update()

        try:
            self.info.markers = self.info.dataset.read_markers()
        except FileNotFoundError:
            lg.info('No notes/markers present in the header of the file')
        else:
            self.notes.update_dataset_marker()
Once you open a dataset, it activates all the widgets.