JSFiddle - React, Tailwind, and code Playground

HTML

<form action="" method="post">

    <select name="MyPopup">
        <option>value 1</option>
        <option>value 2</option>
        <option>value 3</option>
        <option value="-" disabled="disabled" class="SelectSeparator">----</option>    
        <option>value 4</option>
        <option>value 5</option>
        <option>value 6</option>
    </select>
  </form>

CSS

.SelectSeparator
        {
            background-image: url(data:image/gif;base64,R0lGODlhAQABAIAAAAAAAAAAACH5BAAAAAAALAAAAAABAAEAAAICTAEAOw==)
;            
    color:black;
    background-repeat:repeat-x;
            background-position:50% 50%;
            background-attachment:scroll;
}