Scrollable dropdown does not work on mobile

Question

Dropdown will not allow me to scroll or select an option on mobile. It works fine on desktop, and if I simulate mobile in the chrome browser it still works, but when testing on an android device the dropdown will appear when the input is selected, and it shows a scroll bar, but will not let me select anything or scroll through the options.

<div class="scrollable-dropdown-menu">
  <input id="${tableId}-mobile-securityGroups" href=""  type="search" placeholder="A Group"  data-toggle="dropdown" class="form-control typeahead m-b-0 " aria-expanded="false" value="" required>
  <input style="display: none;" id='${tableId}-securityGroupId-mobile' name='securityGroupId'>
</div>

@media (max-width: 500px) {

    .scrollable-dropdown-menu > span > div.tt-menu 
    {
        max-height: 100px;
        overflow-y: scroll;
    }
}

Answer 1

With bootstrap on mobile devices, opening a dropdown adds a .dropdown-backdrop as a tap area for closing dropdown menus when tapping outside the menu. The z-index was 990 for the dropdown-backdrop div putting it in front of my dropdown