title: Overlaying box plot and line plot seaborn
body: <p>I am trying to overlay a box plot (series of box plot based on another variable) and a line plot  of medians of that variable, on the same box plot. A simple code like below works perfectly fine.</p>
  <pre><code>import pandas as pd
  import numpy as np
  import matplotlib.pyplot as plt
  import seaborn as sns
  
  dfx=pd.DataFrame({'S':np.random.randint(10,100,9)*10,'C': 
  ['X','X','X','Y','Y','Y','Z','Z','Z']})
  
  fig,ax=plt.subplots()
  mx=dfx.groupby('C')['S'].median()
  sns.boxplot(y='S',x='C',data=dfx,ax=ax)
  sns.lineplot(y=mx.values,x=mx.index,ax=ax)
  plt.show()
  </code></pre>
  <p>which gives</p>
  <p><a href="https://i.stack.imgur.com/nkmev.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nkmev.png" alt="enter image description here" /></a></p>
  <p>However, when I use the same code for this <a href="https://drive.google.com/open?id=1w0YxgGOu-p2b9J-M9Jl7w39lbYaJFGvz" rel="nofollow noreferrer">data</a> I am reading from csv file, I just cannot the line plot to appear with the box plot.</p>
  <pre><code>import pandas as pd
  import numpy as np
  import matplotlib.pyplot as plt
  import seaborn as sns
  
  df=pd.read_csv('test.csv')
  fig,ax=plt.subplots()
  m=df.groupby('Start Date')['Score'].median()
  sns.boxplot(y='Score',x='Start Date',data=df,ax=ax)
  sns.lineplot(y=m.values,x=m.index,ax=ax)
  plt.show()
  </code></pre>
  <p>gives this
  <a href="https://i.stack.imgur.com/JxDDQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JxDDQ.png" alt="enter image description here" /></a></p>
  <p>It doesn't matter whether the lineplot command is before or after boxplot, only box plot is shown. I see the line only if boxplot line is commented out.</p>
  <p>I do not understand what is different about <a href="https://drive.google.com/open?id=1w0YxgGOu-p2b9J-M9Jl7w39lbYaJFGvz" rel="nofollow noreferrer">this data</a> I am reading from csv that I cannot overlay line and box</p>
  <p>P.S: I know a simple workaround is replace the seaborn lineplot line with matplotlib line command</p>
  <pre><code>ax.plot(m.values,'r-o',linewidth=4)
  </code></pre>
  <p>and it gives the desired result:</p>
  <p><a href="https://i.stack.imgur.com/iZiHp.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iZiHp.png" alt="enter image description here" /></a></p>
  <p>I am just curious why seaborn lineplot is behaving the way it is.</p>