Bootstrap Modal Body Scroll Only

A full height modal dialog, with only the modal-body element scrolling.

HTML

<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap-theme.min.css">
<script src="//code.jquery.com/jquery-3.1.1.min.js"></script>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.12.2/css/bootstrap-select.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.12.2/js/bootstrap-select.js"></script>
<!--// A Basic HTML Page, just standard html elements and innerText values //-->
<div>
  <div>
    <h3>Example: Scrolling the body section of a modal dialog only.</h3>
  </div>
  <div>
    <button class="btn btn-primary" data-toggle="modal" data-target="#dialog-example">
      Show Modal Dialog
    </button>
  </div>
</div>

<div id="dialog-example" class="modal fade" role="dialog" tabindex="-1" aria-labelledby="label-dialog-example" style="display: none;">
  <div class="modal-dialog full-screen" role="document">
    <div class="modal-content">

      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">×</span>
        </button>
        <h4 class="modal-title" id="label-dialog-example">Modal Title Area</h4>
      </div>
      <div class="modal-body">

        <select class="selectpicker" data-size="5">
          <option>Mustard</option>
          <option>Ketchup</option>
          <option>Relish</option>
          <option>Mustard</option>
          <option>Ketchup</option>
          <option>Relish</option>
          <option>Mustard</option>
          <option>Ketchup</option>
          <option>Relish</option>
          <option>Mustard</option>
          <option>Ketchup</option>
          <option>Relish</option>
          <option>Mustard</option>
          <option>Ketchup</option>
         ...

SCSS

.modal-body {
        max-height: calc(110vh - 210px);
        overflow-y: auto;
    }