我在模式窗口中遇到select2的问题。一次同时打开多个select2，这会导致窗口卡在纯js和jquery中。 一次可以打开多个select2。但这会导致页面挂起。当我们在select2之外单击时，select2没有关闭。 我的代码如下。

<div class="custom-content-body mrg-top-adj">
        <div class="insd_custom-content-body auto">
            <div class="auto breadcrumb-outer">
                <button type="button" class=" button ui policy_add" data-toggle="modal"
                        data-target="#add_policy_modal">Add Policy
                </button>
            </div>

            <div id="add_policy_modal" class="modal mymodal" role="dialog" data-backdrop="static">
                <div class="modal-dialog modal-lg">
                    <div class="modal-dialog modal-lg">
                        <div class="modal-content">
                            <div class="modal-content">
                                <div class="modal-header">
                                    <button type="button" class="close" id="form_close_button" data-dismiss="modal">
                                        &times;
                                    </button>
                                    <h4 class="modal-title">Add Policy</h4>
                                </div>
                                <div class="modal-body ui form">
                                    {{--                            <input type="hidden" id="">--}}
                                    <form action="policy-master" method="post" id="policy-master-form"
                                          enctype="multipart/form-data">
                                        <div class="two fields">
                                            <div class="required field">
                                                <label>Class of Policy</label>
                                                <select class="ui select2 select_box" name="class_of_policy"
                                                        id="class-of-policy"
                                                        data-placeholder="Class of Policy" required>
                                                    <option value=""></option>
                                                    <option value="1">Motor</option>
                                                    <option value="2">Fire</option>
                                                </select>
                                            </div>

                                            <div class="required field">
                                                <label>Category</label>
                                                <select class="ui select2 select_box" name="category_id"
                                                        id="category_id"
                                                        data-placeholder="Category" required>
                                                    <option value=""></option>
                                                    <option value="1">General</option>
                                                    <option value="2">Life</option>
                                                </select>
                                            </div>

                                        </div>
                                    </form>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>