<p dir="auto">From version 0.9.0 to version 0.11.0 the "diagonal" on non quadratic pairplots is empty.</p>
<p dir="auto">Sample Code:</p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="import seaborn as sns
import pandas as pd 
from matplotlib import pyplot as plt

test_df = pd.DataFrame({&quot;a&quot;: [1,2,3,4], &quot;b&quot;: [3,4,5,6], &quot;c&quot;: [5,3,6,1]})
sns.pairplot(test_df, x_vars=[&quot;a&quot;], y_vars=[&quot;b&quot;, &quot;c&quot;])
plt.show()"><pre class="notranslate"><span class="pl-k">import</span> <span class="pl-s1">seaborn</span> <span class="pl-k">as</span> <span class="pl-s1">sns</span>
<span class="pl-k">import</span> <span class="pl-s1">pandas</span> <span class="pl-k">as</span> <span class="pl-s1">pd</span> 
<span class="pl-k">from</span> <span class="pl-s1">matplotlib</span> <span class="pl-k">import</span> <span class="pl-s1">pyplot</span> <span class="pl-k">as</span> <span class="pl-s1">plt</span>

<span class="pl-s1">test_df</span> <span class="pl-c1">=</span> <span class="pl-s1">pd</span>.<span class="pl-v">DataFrame</span>({<span class="pl-s">"a"</span>: [<span class="pl-c1">1</span>,<span class="pl-c1">2</span>,<span class="pl-c1">3</span>,<span class="pl-c1">4</span>], <span class="pl-s">"b"</span>: [<span class="pl-c1">3</span>,<span class="pl-c1">4</span>,<span class="pl-c1">5</span>,<span class="pl-c1">6</span>], <span class="pl-s">"c"</span>: [<span class="pl-c1">5</span>,<span class="pl-c1">3</span>,<span class="pl-c1">6</span>,<span class="pl-c1">1</span>]})
<span class="pl-s1">sns</span>.<span class="pl-en">pairplot</span>(<span class="pl-s1">test_df</span>, <span class="pl-s1">x_vars</span><span class="pl-c1">=</span>[<span class="pl-s">"a"</span>], <span class="pl-s1">y_vars</span><span class="pl-c1">=</span>[<span class="pl-s">"b"</span>, <span class="pl-s">"c"</span>])
<span class="pl-s1">plt</span>.<span class="pl-en">show</span>()</pre></div>
<p dir="auto">The top graph is empty although a scatter plot should be shown in place as the two columns have matching indices.</p>
<p dir="auto">Just updated to seaborn 0.11.0 and matplotlib 3.3.1.</p>
<p dir="auto">Run this code:</p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="iris = sns.load_dataset(&quot;iris&quot;)
sns.pairplot(data=iris, hue=&quot;species&quot;, y_vars='sepal_width');
sns.pairplot(data=iris, hue=&quot;species&quot;, y_vars='sepal_width', x_vars=['sepal_length', 'petal_length']);"><pre class="notranslate"><span class="pl-s1">iris</span> <span class="pl-c1">=</span> <span class="pl-s1">sns</span>.<span class="pl-en">load_dataset</span>(<span class="pl-s">"iris"</span>)
<span class="pl-s1">sns</span>.<span class="pl-en">pairplot</span>(<span class="pl-s1">data</span><span class="pl-c1">=</span><span class="pl-s1">iris</span>, <span class="pl-s1">hue</span><span class="pl-c1">=</span><span class="pl-s">"species"</span>, <span class="pl-s1">y_vars</span><span class="pl-c1">=</span><span class="pl-s">'sepal_width'</span>);
<span class="pl-s1">sns</span>.<span class="pl-en">pairplot</span>(<span class="pl-s1">data</span><span class="pl-c1">=</span><span class="pl-s1">iris</span>, <span class="pl-s1">hue</span><span class="pl-c1">=</span><span class="pl-s">"species"</span>, <span class="pl-s1">y_vars</span><span class="pl-c1">=</span><span class="pl-s">'sepal_width'</span>, <span class="pl-s1">x_vars</span><span class="pl-c1">=</span>[<span class="pl-s">'sepal_length'</span>, <span class="pl-s">'petal_length'</span>]);</pre></div>
<p dir="auto">And saw it:<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/24957288/92593736-438e9000-f2aa-11ea-93ac-3fb7b2c94a68.PNG"><img src="https://user-images.githubusercontent.com/24957288/92593736-438e9000-f2aa-11ea-93ac-3fb7b2c94a68.PNG" alt="screen" style="max-width: 100%;"></a></p>
<p dir="auto">And this problem appeared in all previously created pairplots, that have parameter y_vars</p>