old_contents: """
  Display a bar's height and name on top of it upon hovering
  ==========================================================
  
  Using an event handler to change the annotation text and position.
  """
  
  import string
  import matplotlib.pyplot as plt
  import mplcursors
  
  fig, ax = plt.subplots()
  ax.bar(range(9), range(1, 10), align="center")
  labels = string.ascii_uppercase[:9]
  ax.set(xticks=range(9), xticklabels=labels, title="Hover over a bar")
  
  cursor = mplcursors.cursor(hover=True)
  @cursor.connect("add")
  def on_add(sel):
      x, y, width, height = sel.artist[sel.target.index].get_bbox().bounds
      sel.annotation.set(text=f"{x+width/2}: {height}", position=(0, 20))
      sel.annotation.xy = (x + width / 2, y + height)
  
  plt.show()
  
new_contents: """
  Display a bar's height and name on top of it upon hovering
  ==========================================================
  
  Using an event handler to change the annotation text and position.
  """
  
  import string
  import matplotlib.pyplot as plt
  import mplcursors
  
  fig, ax = plt.subplots()
  ax.bar(range(9), range(1, 10), align="center")
  labels = string.ascii_uppercase[:9]
  ax.set(xticks=range(9), xticklabels=labels, title="Hover over a bar")
  
  cursor = mplcursors.cursor(hover=True)
  @cursor.connect("add")
  def on_add(sel):
      x, y, width, height = sel.artist[sel.target.index].get_bbox().bounds
      sel.annotation.set(text=f"{x+width/2}: {height}",
                         position=(0, 20), anncoords="offset points")
      sel.annotation.xy = (x + width / 2, y + height)
  
  plt.show()
  
subject: Fix bar example by setting anncoords.