Here am using jquery multiselect. When I click on a item it is moving from one select box to another one, but I need just to copy from a select box to another one. I want clicked item always available to left select box. Any suggestions? 

```js
$(document).ready(function() {
  $('#undo_redo').multiselect();
});
```

```html
<link href="https://www.jqueryscript.net/css/jquerysctipttop.css" rel="stylesheet" type="text/css">
<link rel="stylesheet" href="https://netdna.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css">
<script src="https://code.jquery.com/jquery-1.11.2.min.js"></script>
<script src="https://netdna.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>
<script src="https://www.jqueryscript.net/demo/Two-side-Multi-Select-Plugin-with-jQuery-multiselect-js/js/multiselect.js"></script>
<div class="container">
  <h1 style="margin:10px auto 50px auto; text-align:center">jQuery multiselect.js Example</h1>
  <div class="row">
    <div class="col-xs-5">
      <select name="from" id="undo_redo" class="form-control" size="13" multiple="multiple">
        <option value="1">C++</option>
        <option value="2">C#</option>
        <option value="3">Haskell</option>
        <option value="4">Java</option>
        <option value="5">JavaScript</option>
        <option value="6">Lisp</option>
        <option value="7">Lua</option>
        <option value="8">MATLAB</option>
        <option value="9">NewLISP</option>
        <option value="10">PHP</option>
        <option value="11">Perl</option>
        <option value="12">SQL</option>
        <option value="13">Unix shell</option>
      </select>
    </div>
    <div class="col-xs-2">
      <button type="button" id="undo_redo_undo" class="btn btn-primary btn-block">undo</button>
      <button type="button" id="undo_redo_rightAll" class="btn btn-default btn-block"><i class="glyphicon glyphicon-forward"></i></button>
      <button type="button" id="undo_redo_rightSelected" class="btn btn-default btn-block"><i class="glyphicon glyphicon-chevron-right"></i></button>
      <button type="button" id="undo_redo_leftSelected" class="btn btn-default btn-block"><i class="glyphicon glyphicon-chevron-left"></i></button>
      <button type="button" id="undo_redo_leftAll" class="btn btn-default btn-block"><i class="glyphicon glyphicon-backward"></i></button>
      <button type="button" id="undo_redo_redo" class="btn btn-warning btn-block">redo</button>
    </div>
    <div class="col-xs-5">
      <select name="to" id="undo_redo_to" class="form-control" size="13" multiple="multiple"></select>
    </div>
  </div>
</div>
```