jQuery & jQueryUI Base

HTML

<link rel="stylesheet" href="http://ajax.microsoft.com/ajax/jquery.ui/1.8.7/themes/black-tie/jquery-ui.css">
<script src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.9/jquery-ui.js"></script>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>jQuery UI Sortable - Default functionality</title>
  <link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
  <link rel="stylesheet" href="/resources/demos/style.css">
  <style>
  #sortable { list-style-type: none; margin: 0; padding: 0; width: 60%; }
  #sortable li { margin: 0 3px 3px 3px; padding: 0.4em; padding-left: 1.5em; font-size: 1.4em; height: 18px; }
  #sortable li span { position: absolute; margin-left: -1.3em; }
  </style>
  <script src="https://code.jquery.com/jquery-1.12.4.js"></script>
  <script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>

</head>
<body>
 
 <div class="smallfry">
   <ul id="sortable">
    <li class="ui-state-default">Item 1<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a</li>
    <li class="ui-state-default"><br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a</li>
    <li class="ui-state-default"><br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a</li>
    <li class="ui-state-default">Item 4</li>
    <li class="ui-state-default">Item 5</li>
    <li class="ui-state-default"><br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a<br>a</li>
    <li class="ui-state-default">Item 7</li>
  </ul>
 </div> 
 
</body>

CSS

#sortable li {
  height: auto !important;
}

.ui-sortable-placeholder {
    height: 3px;
    display: block;
    background: red;
    visibility: visible;
    color: yellow;
}

.smallfry {
  padding: 20px;
    display: inline-block;
    width: 400px;
    height: 496px;
    background: rebeccapurple;
    overflow: auto;
}

JavaScript

function test() {
    $('.ui-sortable-placeholder').css('visibility', 'visible');
  }
  
  function test2() {
    $('.ui-sortable-placeholder').css('visibility', 'none');
  }

  $( function() {
    $( "#sortable" ).sortable({
    	scroll: true,
      start: test,
      stop: test2
    });
  } );