JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.12.2/css/bootstrap-select.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.12.2/js/bootstrap-select.min.js"></script>
<link rel="stylesheet" href="cdn.datatables.net/1.10.22/css/jquery.dataTables.min.css">
<script src="cdn.datatables.net/1.10.22/js/jquery.dataTables.min.js"></script>
<script src="code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<link rel="stylesheet" href="code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
<script src="cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.9.0/js/bootstrap-datepicker.min.js"></script>
<link rel="stylesheet" href="cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.9.0/css/bootstrap-datepicker.min.css">
<select class="selectpicker form-control" data-size="40px" data-width="210px" style="height: 80px" data-live-search="true" data-none-Selected-Text="" data-hide-disabled="true" data-container="body" name="mittente_nucleo" id="mittente_nucleo"><option></option><option>1</option><option>2</option></select>

CSS

.bootstrap-select.btn-group .dropdown-toggle:not([title=""]) .filter-option {
  background-color: yellow !important;
}