For drooping the snippet onto the page first we have to open the src file, add some class and css feature in css file and jas file after that clicks on an option, the system will add the class specified in the data-select_class attribute.
By replacing data-select_class with data-toggle_class you will be able to select more classes at the same time. For example you can see below.

<template id="snippet_testimonial_opt" name="Snippet Testimonial Options" inherit_id="website_less.snippet_options">
  <xpath expr="//div[@data-js='background']" position="after">
    <div data-selector=".snippet_testimonial"> <!-- Options group -->
      <li class="dropdown-submenu">
        <a href="#">Your Option</a>
        <ul class="dropdown-menu"> <!-- Options list -->
          <li data-select_class="opt_shadow"><a>Shadow Images</a></li>
          <li data-select_class="opt_grey_bg"><a>Grey Bg</a></li>
          <li data-select_class=""><a>None</a></li>
        </ul>
      </li>
    </div>
  </xpath>
 </template>