用HTML5打开对话框后面的Select2 .showmodal（）

Question

在对话框模态窗口后面选择2打开选择列表。 Chrome 49.

<dialog id="hello" class="alert">
    <div style="padding:10px">
        Imagine some great content here.
    </div>
    <div class="linksTable">
      <select name="wpmse_options[social_list]" id="mse_social_list" class="input-block-level wpmse_select2" required>
       </select>

    </div>
    <footer>
        <div class="toolbar-actions">
            <button id="cancel" class="btn btn-default">Cancel</button>
            <button id="save" class="btn btn-primary pull-right">Save</button>
        </div>
    </footer>
</dialog>

http://jsfiddle.net/memoris/f0sma9tf/6/