图像未显示在选择框中（Twitter Bootstrap插件）

我试图创建一个选择框，显示所有带有文本的Twitter Bootstrap图标。因此，我正在使用Bootstrap-Select插件。其中一张图像显示在列表中，但其余的图像以某种方式被隐藏。

为了获得所有列出的图标及其文字的列表，我必须更改什么？

JS：

<script src="source/bootstrap_select/bootstrap-select.js" type="text/javascript"></script>

<script type="text/javascript">
    $( document ).ready(function() {
        $('.selectpicker').selectpicker('');
    });
</script>

HTML：

<select class="selectpicker">
    <option data-icon="icon-search">icon-search</option>
    <option data-icon="icon-envelope">icon-envelope</option>
    <option data-icon="icon-heart" selected="selected">icon-heart</option>
    <option data-icon="icon-star">icon-star</option>
    <option data-icon="icon-star-empty">icon-star-empty</option>
    <option data-icon="icon-user">icon-user</option>
    <option data-icon="icon-film">icon-film</option>
    <option data-icon="icon-th-large">icon-th-large</option>
    <option data-icon="icon-th">icon-th</option>
    <option data-icon="icon-th-list">icon-th-list</option>
    <option data-icon="icon-ok">icon-ok</option>
    <option data-icon="icon-remove">icon-remove</option>
    <option data-icon="icon-zoom-in">icon-zoom-in</option>
    <option data-icon="icon-zoom-out">icon-zoom-out</option>
    <option data-icon="icon-off">icon-off</option>
    <option data-icon="icon-signal">icon-signal</option>
    <option data-icon="icon-cog">icon-cog</option>
    <option data-icon="icon-trash">icon-trash</option>
    <option data-icon="icon-home">icon-home</option>
    <option data-icon="icon-file">icon-file</option>
    <option data-icon="icon-time">icon-time</option>
    <option data-icon="icon-road">icon-road</option>
    <option data-icon="icon-download-alt">icon-download-alt</option>
    <option data-icon="icon-download">icon-download</option>
    <option data-icon="icon-upload">icon-upload</option>
    <option data-icon="icon-inbox">icon-inbox</option>
    <option data-icon="icon-play-circle">icon-play-circle</option>
    <option data-icon="icon-repeat">icon-repeat</option>
    <option data-icon="icon-refresh">icon-refresh</option>
    <option data-icon="icon-list-alt">icon-list-alt</option>
    <option data-icon="icon-lock">icon-lock</option>
    <option data-icon="icon-flag">icon-flag</option>
    <option data-icon="icon-headphones">icon-headphones</option>
    <option data-icon="icon-glass">icon-glass</option>
    <option data-icon="icon-music">icon-music</option>
</select>