title: seaborn joyplot does not fill all the way to the top
body: <p>I'm using <code>seaborn</code> in Python 3.5. Taking the example joy plot from the gallery, modified slightly to save the figure:</p>
  
  <pre><code>import numpy as np
  import pandas as pd
  import seaborn as sns
  import matplotlib.pyplot as plt
  sns.set(style="white", rc={"axes.facecolor": (0, 0, 0, 0)})
  
  # Create the data
  rs = np.random.RandomState(1979)
  x = rs.randn(500)
  g = np.tile(list("ABCDEFGHIJ"), 50)
  df = pd.DataFrame(dict(x=x, g=g))
  m = df.g.map(ord)
  df["x"] += m
  
  # Initialize the FacetGrid object
  pal = sns.cubehelix_palette(10, rot=-.25, light=.7)
  g = sns.FacetGrid(df, row="g", hue="g", aspect=15, size=.5, palette=pal)
  
  # Draw the densities in a few steps
  g.map(sns.kdeplot, "x", clip_on=False, shade=True, alpha=1, lw=1.5, bw=.2)
  g.map(sns.kdeplot, "x", clip_on=False, color="w", lw=2, bw=.2)
  g.map(plt.axhline, y=0, lw=2, clip_on=False)
  
  # Define and use a simple function to label the plot in axes coordinates
  def label(x, color, label):
      ax = plt.gca()
      ax.text(0, .2, label, fontweight="bold", color=color,
              ha="left", va="center", transform=ax.transAxes)
  
  g.map(label, "x")
  
  # Set the subplots to overlap
  g.fig.subplots_adjust(hspace=-.25)
  
  # Remove axes details that don't play will with overlap
  g.set_titles("")
  g.set(yticks=[])
  g.despine(bottom=True, left=True)
  plt.savefig('tmp.png')
  </code></pre>
  
  <p>There is a slight visual defect, namely the KDEs do not quite fill all the way to the top. This is most visible in rows B, G, H and J:</p>
  
  <p><a href="https://i.stack.imgur.com/MXT8U.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MXT8U.png" alt="enter image description here"></a></p>
  
  <p>Any idea what's causing this?</p>