Bootstrap：手风琴顶部的下拉菜单

Question

我有一个 bootstrap 4 下拉菜单，它位于 bootstrap 手风琴的主体内：

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css" integrity="sha384-GJzZqFGwb1QTTN6wy59ffF1BuGJpLSa9DkKMp0DgiMDm4iYMj70gZWKYbI706tWS" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js" integrity="sha384-wHAiFfRlMFy6i5SRaxvfOCifBUQy1xHdJ/yoi7FRNXMRBu5WHdZYu1hA6ZOblgut" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.min.js" integrity="sha384-B0UglyR+jN6CkvvICOB2joaf5I4l3gm9GU6Hc1og6Ls7i6U/mkkaduKaBhlAXv9k" crossorigin="anonymous"></script>

<div class="accordion mb-3" id="testAccordion">
    <div class="card">
        <div class="card-header" id="accordionAHeading">
            <h2 class="mb-0">
                <button class="btn btn-link" type="button" data-toggle="collapse" data-target="#accordionACollapse">
                Lalala
                </button>
            </h2>
        </div>
        <div id="accordionACollapse" class="collapsed collapse show" data-parent="#testAccordion">
            <div class="card-body">
                <h5>Lalala</h5>

                <div class="dropdown" id="addElementDropdown">
                    <button class="btn btn-primary dropdown-toggle" type="button" id="addElementDropdownButton" data-toggle="dropdown">Dropdown</button>
                    <div class="dropdown-menu" aria-labelledby="addElementDropdownButton">
                        <a class="dropdown-item" href="#">Item 1</a>
                        <a class="dropdown-item" href="#">Item 2</a> 
                        <a class="dropdown-item" href="#">Item 3</a>
                        <a class="dropdown-item" href="#">Item 4</a>
                        <a class="dropdown-item" href="#">Item 5</a>
                    </div>
                </div>
            </div>
        </div>
    </div>

    <div class="card">
        <div class="card-header" id="accordionBHeading">
            <h2 class="mb-0">
                <button class="btn btn-link collapsed" type="button" data-toggle="collapse" data-target="#accordionBCollapse">
                Test
                </button>
            </h2>
        </div>
        <div id="accordionBCollapse" class="collapse collapsed" data-parent="#testAccordion">
            <div class="card-body">
                <h5>Test</h5>

                <div class="dropdown" id="addElementDropdown">
                    <button class="btn btn-primary dropdown-toggle" type="button" id="addElementDropdownButton" data-toggle="dropdown">Dropdown</button>
                    <div class="dropdown-menu" aria-labelledby="addElementDropdownButton">
                        <a class="dropdown-item" href="#">Item 1</a>
                        <a class="dropdown-item" href="#">Item 2</a> 
                        <a class="dropdown-item" href="#">Item 3</a>
                        <a class="dropdown-item" href="#">Item 4</a>
                        <a class="dropdown-item" href="#">Item 5</a>
                    </div>
                </div>
            </div>
        </div>
    </div>
</div>

不幸的是，下拉菜单被绘制在手风琴后面。我已经尝试添加一些包含position: relative到手风琴和卡片的样式，以及不同的z-index-values，但没有机会。有任何想法吗？

更新：我已将代码片段粘贴到tryit 编辑器中

更新 2：我还对上述代码进行了截屏：

Answer 1

这是因为您的卡片类中隐藏了溢出。将此添加到您的 CSS

.accordion .card {
    overflow: inherit;
}