title: Matplotlib missing x tick labels
body: <p>Once I run the code below, the x tick labels for the third plot, ax3, does not show up. Yet, I only removed the x tick labels for ax1 and ax2. Any solution to having the dates appear on the x axis of my third plot, ax3?</p>
  
  <pre><code>plt.figure()
  ax1 = plt.subplot2grid((8,1),(0,0), rowspan=4, colspan=1)
  ax1.yaxis.set_major_locator(mticker.MaxNLocator(nbins=10, prune='lower'))
  plt.setp(ax1.get_xticklabels(), visible=False)
  
  ax2 = plt.subplot2grid((8,1),(4,0), rowspan=2, colspan=1, sharex = ax1)
  plt.setp(ax2.get_xticklabels(), visible=False)
  
  ax3 = plt.subplot2grid((8,1),(6,0), rowspan=2, colspan=1, sharex = ax1)
  ax3.xaxis.set_major_locator(mticker.MaxNLocator(10))
  ax3.xaxis.set_minor_locator(mticker.MaxNLocator(20))
  
  '''
  # This has been ***removed*** in corrected version
  for label in ax3.xaxis.get_ticklabels():
          label.set_rotation(45)
          plt.xlabel('Dates') #This label does not appear in the figure either
  '''
  
  ax3.yaxis.set_major_locator(mticker.MaxNLocator(nbins=5, prune='upper'))
  
  main.dropna(inplace=True)                          
  main['sales1'].plot(ax=ax1)
  main['sales2'].plot(ax=ax1)
  cmain.plot(ax=ax2)
  main[['rollsales1', 'rollsales2']].plot(ax=ax3)
  
  '''
  # This has been added to corrected version.   
  plt.setp(ax3.xaxis.get_label(), visible=True, text='Dates')
  plt.setp(ax3.get_xticklabels(), visible=True, rotation=30, ha='right')
  '''    
  
  plt.show()
  </code></pre>