<!-- Button trigger modal -->

<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#basicExampleModal">

Launch demo modal

</button>

​

<!-- Modal -->

<div class="modal fade" id="basicExampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">

 <div class="modal-dialog" role="document">

  <div class="modal-content">

   <div class="modal-header">

    <h5 class="modal-title" id="exampleModalLabel">Modal title</h5>

    <button type="button" class="close" data-dismiss="modal" aria-label="Close">

     <span aria-hidden="true">&times;</span>

    </button>

   </div>

   <div class="modal-body">

    works fine:

    <select class="mdb-select md-form">

     <option value="" disabled selected>Choose your option</option>

     <option value="1">Option 1</option>

     <option value="2">Option 2</option>

     <option value="3">Option 3</option>

     <option value="4">Option 4</option>

     <option value="5">Option 5</option>

    </select>

​

    don't work:

    <select class="mdb-select md-form">

     <option value="" disabled selected>Choose your option</option>

     <option value="1">Option 1</option>

     <option value="2">Option 2</option>

     <option value="3">Option 3</option>

     <option value="4">Option 4</option>

     <option value="5">Option 5</option>

     <option value="6">Option 6</option>

    </select>

   </div>

   <div class="modal-footer">

    <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>

    <button type="button" class="btn btn-primary">Save changes</button>

   </div>

  </div>

 </div>

</div>