bootstrap 4多级下拉菜单-第二级首先隐藏然后显示

Question

在这个示例中，我有一个菜单项。下拉菜单的第一级工作正常，但是使用此jQuery代码的第二级效果不好。您可以看到，如果您单击Menu4.4，那么它首先将隐藏菜单并再次显示（如闪烁一个菜单）。我该如何解决或纠正此行为？

$(function() {
  "use strict";
  // dropdown slide in navigation
  $(".dropdown").on("show.bs.dropdown", function() {
    $(this).find(".dropdown-menu").first().stop(true, true).slideDown();
  });
  // dropdown slide in navigation
  $(".dropdown").on("hide.bs.dropdown", function() {
    $(this).find(".dropdown-menu").first().stop(true, true).slideUp();
  });
});

.navbar-nav li .nav-link {
  padding-right: .5rem;
  padding-left: .5rem;
}

#navbarCollapse li.active {
  background-color: #BA122B;
}

#navbarCollapse li.active a {
  color: #FFF;
  background-color: #BA122B;
}

#navbarCollapse .menu {
  padding-top: 30px;
}

#navbarCollapse .dropdown-menu {
  padding-left: 20px;
}

#navbarCollapse li a {
  border-bottom: 1px solid #E3E3E3;
  color: #BA122B;
  -webkit-transition-duration: 0.3s;
  transition-duration: 0.3s;
  -webkit-transition-property: color, background-color;
  transition-property: color, background-color;
  -webkit-transform: perspective(1px) translateZ(0);
  transform: perspective(1px) translateZ(0);
}

#navbarCollapse li a:hover {
  color: #FFF;
  background-color: #BA122B;
}

#navbarCollapse parent:after {}

.body {
  background-color: #f6f6f6;
  padding-top: 2rem;
}

.off-canvas-active .off-canvas-overlay {
  opacity: 1;
  visibility: visible;
}

.off-canvas-overlay {
  position: fixed;
  right: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, .75);
  z-index: 1000;
  visibility: hidden;
  opacity: 0;
  transition: .3s ease-in-out;
}

.offcanvas-collapse.open {
  display: block;
  -webkit-animation: slide-right .3s ease-out;
  -moz-animation: slide-right .3s ease-out;
}

@-webkit-keyframes slide-right {
  0% {
    opacity: 0;
    -webkit-transform: translateX(-100%);
  }
  100% {
    opacity: 1;
    -webkit-transform: translateX(0);
  }
}

@-moz-keyframes slide-right {
  0% {
    opacity: 0;
    -moz-transform: translateX(-100%);
  }
  100% {
    opacity: 1;
    -moz-transform: translateX(0);
  }
}

.offcanvas-collapse {
  position: fixed;

  bottom: 0;
  right: 0;
  width: 330px;
  transition-timing-function: ease-in-out;
  transition-duration: .3s;
  transition-property: width;
  display: none;
  overflow-y: auto;
}

.navbar-expand-md .navbar-toggler {
  display: block!important;
}

.navbar-toggler {
  border: none;
  height: 40px;
}

.navbar-toggler:active,
.navbar-toggler:focus {
  outline: 0;
}

.navbar-toggler .icon-bar {
  display: block;
  width: 30px;
  height: 2px;
  border-radius: 1px;
  transition: .3s ease-in-out;
  background-color: #BA122B;
}

.navbar-dark .navbar-toggler .icon-bar {
  background: #ffffff;
}

.navbar-toggler .icon-bar:nth-of-type(1) {
  transform: rotate(45deg) translate(2px, 2px);
}

.navbar-toggler .icon-bar:nth-of-type(2) {
  opacity: 0;
}

.navbar-toggler .icon-bar:nth-of-type(3) {
  transform: rotate(-45deg) translate(1px, -1px);
}

.navbar-toggler.collapsed .icon-bar {
  margin: 5px auto;
  transform: none;
  opacity: 1;
}

.navbar-nav .dropdown-menu {
  padding: 0;
  border: none;
  margin: 0;
  border-radius: 0;
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">


<script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>


<nav class="offcanvas-collapse navbar open" id="navbarCollapse">
  <div class="menu-body bg-white open" style="left: 1267.5px;">
    <ul class="nav menu navbar-nav ml-auto text-uppercase mod-list">
      <li class="item-103 default current active"><a href="#" class="nav-link">Home!</a></li>
      <li class="item-111"><a href="#" class="nav-link">Menu1</a></li>
      <li class="item-104 deeper parent dropdown"><a href="#" class="nav-link dropdown-toggle" data-toggle="dropdown" aria-expanded="false">Menu2</a>
        <ul class="nav-child unstyled small dropdown-menu" style="display: none;">
          <li class="item-105"><a href="#" class="nav-link">Menu2.1</a></li>
          <li class="item-106"><a href="#" class="nav-link">Menu2.2</a></li>
        </ul>
      </li>
      <li class="item-112 deeper parent dropdown"><a href="#" class="nav-link dropdown-toggle" data-toggle="dropdown" aria-expanded="false">Menu3</a>
        <ul class="nav-child unstyled small dropdown-menu" style="display: none;">
          <li class="item-114"><a href="#" class="nav-link">Menu3.1</a></li>
          <li class="item-115"><a href="#" class="nav-link">Menu3.2</a></li>
          <li class="item-116"><a href="#" class="nav-link">Menu3.3</a></li>
          <li class="item-117"><a href="#" class="nav-link">Menu3.4</a></li>
        </ul>
      </li>
      <li class="item-118 deeper parent dropdown"><a href="#" class="nav-link dropdown-toggle" data-toggle="dropdown" aria-expanded="false">Menu4</a>
        <ul class="nav-child unstyled small dropdown-menu" style="display: none;">
          <li class="item-119"><a href="#" class="nav-link">Menu4.1</a></li>
          <li class="item-142"><a href="#" class="nav-link">Menu4.2</a></li>
          <li class="item-143"><a href="#" class="nav-link">Menu4.3</a></li>
          <li class="item-154 deeper parent dropdown"><a href="#" class="nav-link dep dropdown-toggle" data-toggle="dropdown" aria-expanded="false">Menu4.4</a>
            <ul class="nav-child unstyled small dropdown-menu" style="display: none;">
              <li class="item-155"><a href="#" class="nav-link">Menu4.4.1</a></li>
              <li class="item-156"><a href="#" class="nav-link">Menu4.4.2</a></li>
            </ul>
          </li>
          <li class="item-157"><a href="#" class="nav-link">Menu4.5</a></li>
        </ul>
      </li>
      <li class="item-137 deeper parent dropdown"><a href="#" class="nav-link dropdown-toggle" data-toggle="dropdown" aria-expanded="false">Menu5</a>
        <ul class="nav-child unstyled small dropdown-menu">
          <li class="item-138"><a href="#" class="nav-link">Menu5.1</a></li>
          <li class="item-139"><a href="#" class="nav-link">Menu5.2</a></li>
        </ul>
      </li>
      <li class="item-140"><a href="#" class="nav-link">Menu6</a></li>
    </ul>
  </div>
</nav>