title: Trying to create a stacked bar chart of the top 10 issues per month
body: <p>I have a stacked series that looks like the following (date is represented as just a month integer):</p>
  
  <pre>
  date  issues        size                        
  1     issue1        1
        issue2        2
        issue3        1
        issue4        6
        issue5        1
  ...
  8     issue1        1
        issue2        2
        issue3        1
        issue4        6
        issue5        1
  </pre>
  
  <p>I can create the stacked bar chart by just graphing with</p>
  
  <pre><code>series.unstack().fillna(0)
  </code></pre>
  
  <p>but I want to limit the number of issues to only the top 10 by size per date, as there are currently over 100. This is the part I cannot figure out. Any help is appreciated.</p>
  
  <p>Edit:</p>
  
  <p>Here is what my original DataFrame looks like for more clarity.</p>
  
  <pre>
            date  issues
  0            1  issue1 
  1            1  issue2 
  2            1  issue3 
  3            1  issue1
  4            1  issue3 
  5            2  issue1 
  6            2  issue2 
  7            2  issue3
  ...
  </pre>