you can also check this section of github page
<select id="nosearch-listbox" data-search="false" class="dual-listbox" multiple> <option value="1">Cheese</option> <option value="2">Egg</option> <option value="3">Butter</option> <option value="4">Margarine</option> <option value="5">Yogurt</option> <option value="6">Pizza</option> <option value="7">Steak</option> <option value="8">Kebab</option> <option value="9">Sandwich</option> <option value="10">Hamburger</option></select>
// JAVASCRIPT CODElet nosearchListbox = new DualListbox('#nosearch-listbox'); nosearchListbox.search_left.classList.add('dual-listbox__search--hidden'); nosearchListbox.search_right.classList.add('dual-listbox__search--hidden');