whmcsDNSManager/modules/addons/DNSManager2/templates/admin/pages/tools/modal/add-import.tpl

<div class="modal fade">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">&times;</span><span class="sr-only">{$MGLANG->T('close')}</span></button>
                <h4 class="modal-title">{$MGLANG->T('add_import')}</h4>
            </div>
            <div class="modal-body">
                <form class="form-horizontal" role="form">
                    <div class="form-group">
                        <label for="a1" class="col-sm-3 control-label">{$MGLANG->T('from_server')}</label>
                        <div class="col-sm-9">
                            <select class="select2" name="from_server" id="a1" required>
                            {foreach from=$servers item="server"}
                                <option value="{$server->id}">{$server->name}</option>
                            {foreachelse}
                                <option value="" disabled="">{$MGLANG->T('no_server_available')}</option>
                            {/foreach}
                            </select>
                        </div>
                    </div>
                </form>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default btn-inverse" data-dismiss="modal">{$MGLANG->T('close')}</button>
                <button type="button" class="btn btn-primary btn-inverse" data-act="addImportSave">{$MGLANG->T('add')}</button>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->