In bootstrap 4 alpha 6 dropdown menus don't open. These jQuery listeners fix it.

fix-bootstrap-4-dropdown-menus.js

$(document).on('click', ".dropdown [data-toggle=dropdown]", function(eve){
  const button = $(eve.target),
    dropdownContainer = button.parent(".dropdown");
  
  const closeMenu = function() {
    dropdownContainer.removeClass("show");
    $(document).unbind("click", docListener);
    $("a", dropdownContainer).unbind("click", menuClickListener);
  };

  const docListener = function(ev) {
    const target = $(ev.target);
    if ($.contains(dropdownContainer[0], target[0])) {
      // clicked link in menu
    } else {
      closeMenu();
    }
  };

  const menuClickListener = function(ev) {
    setTimeout(closeMenu, 100);
  };

  dropdownContainer.addClass("show");
  
  $("a", dropdownContainer).click(menuClickListener);
  $(document).click(docListener);
});