title: bootstrap select dropdown can't follow the parent
body: <p>I use the bootstrap-select picker to select picker option. When I scroll the container, drop-down struct with the top bar.it doesn't properly follow the parent element.</p>
  
  <p>please check the codepen for it: <a href="https://codepen.io/Arunkarthik07/pen/bjOLYV" rel="nofollow noreferrer">https://codepen.io/Arunkarthik07/pen/bjOLYV</a> </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>    .container{ 
        height: auto;
        overflow-y: scroll;
      } </code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>    &lt;div&gt;
      &lt;nav class="navbar navbar-light bg-light"&gt;
        &lt;span class="navbar-brand mb-0 h1"&gt;Navbar&lt;/span&gt;
      &lt;/nav&gt;
      &lt;div class="container"&gt;
       
      &lt;select class="selectpicker"&gt;
        &lt;option&gt;Mustard&lt;/option&gt;
        &lt;option&gt;Ketchup&lt;/option&gt;
        &lt;option&gt;Barbecue&lt;/option&gt;
          &lt;option&gt;Mustard&lt;/option&gt;
        &lt;option&gt;Ketchup&lt;/option&gt;
        &lt;option&gt;Barbecue&lt;/option&gt;
      &lt;/select&gt;  
            
      &lt;table&gt;
        &lt;tr&gt;
          &lt;th&gt;Company&lt;/th&gt;
          &lt;th&gt;Contact&lt;/th&gt;
          &lt;th&gt;Country&lt;/th&gt;
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;Alfreds Futterkiste&lt;/td&gt;
          &lt;td&gt;Maria Anders&lt;/td&gt;
          &lt;td&gt;Germany&lt;/td&gt;
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;Centro comercial Moctezuma&lt;/td&gt;
          &lt;td&gt;Francisco Chang&lt;/td&gt;
          &lt;td&gt;Mexico&lt;/td&gt;
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;Ernst Handel&lt;/td&gt;
          &lt;td&gt;Roland Mendel&lt;/td&gt;
          &lt;td&gt;Austria&lt;/td&gt;
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;Island Trading&lt;/td&gt;
          &lt;td&gt;Helen Bennett&lt;/td&gt;
          &lt;td&gt;UK&lt;/td&gt;
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;Laughing Bacchus Winecellars&lt;/td&gt;
          &lt;td&gt;Yoshi Tannamuri&lt;/td&gt;
          &lt;td&gt;Canada&lt;/td&gt;
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;Magazzini Alimentari Riuniti&lt;/td&gt;
          &lt;td&gt;Giovanni Rovelli&lt;/td&gt;
          &lt;td&gt;Italy&lt;/td&gt;
        &lt;/tr&gt;
      &lt;/table&gt;
       
      &lt;/div&gt;
      &lt;/div&gt;
      &lt;/div&gt;</code></pre>
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  </div>
  </p>
  
  <p><a href="https://i.stack.imgur.com/Pfylc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Pfylc.png" alt="enter image description here"></a></p>