code: def display(self):
          
          lg.debug('GraphicsScene is between {}s and {}s'.format(self.minimum,
                                                                 self.maximum))
  
          x_scale = 1 / self.parent.value('overview_scale')
          lg.debug('Set scene x-scaling to {}'.format(x_scale))
  
          self.scale(1 / self.transform().m11(), 1)  # reset to 1
          self.scale(x_scale, 1)
  
          self.scene = QGraphicsScene(self.minimum, 0,
                                      self.maximum,
                                      TOTAL_HEIGHT)
          self.setScene(self.scene)
  
          # reset annotations
          self.idx_markers = []
          self.idx_annot = []
  
          self.display_current()
  
          for name, pos in BARS.items():
              item = QGraphicsRectItem(self.minimum, pos['pos0'],
                                       self.maximum, pos['pos1'])
              item.setToolTip(pos['tip'])
              self.scene.addItem(item)
  
          self.add_timestamps()
docs: Updates the widgets, especially based on length of recordings.