JSFiddle - React, Tailwind, and code Playground

HTML

<div class="buttonClass">
    <button>Button</button>
    <ul>
        <li>
        <ul>
        <li>
        <div class="modal-dialog modal-lg" id="dvNewIncident" role="dialog">
                                            <form action="" id="form_Incident" style="margin: 0; padding: 3px 15px" accept-charset="utf-8">
                                                <fieldset class="control-group">
                                                    <div class="form-horizontal">
                                                        <div class="form-group">
                                                            <label class="col-lg-2 control-label">Device: </label>
                                                            <div class="col-lg-4">
                                                                <select class="form-control" id="drp_nIncident_SubCategory">
                                                                    <option value="ALL">ALL</option>
                                                                    <option value="Film">Film</option>
                                                                    <option value="LMS/TMS">LMS/TMS</option>
                                                                    <option value="Computer">Computer</option>
                                                                    <option value="Monitor">Monitor</option>
                                                                    <option value="Screen">Screen</option>
                                                                    <option value="Automation">Automation</option>
                                                                    <option value="Phone">Phone</option>
                                                                    <option value="Special Events">Special Events</option>
                                                                    <option value="Projectors">Projectors</option>
             ...

CSS

.buttonClass>ul {
    display: none;
}
.buttonClass:hover>ul {
    display: block;
}