[jquery] Jquery date picker z-index issue

I had this issue as well, since the datepicker uses the input's z-index, I added the following css

#dialogID input,.modal-dialog input, .modal-dialog .input-group .form-control{
  z-index:inherit;
}

Just take the rule that applies to yours, either by parent id, class, or in my case a bootstrap dialog, using their input-group and form-control.