.bootstrap-datetimepicker-widget.dropdown-menu{
    display: block!important;
    opacity: 1;

    -moz-transition:    opacity 1000ms ease;
    -webkit-transition: opacity 1000ms ease;
    -o-transition:      opacity 1000ms ease;
    -ms-transition:     opacity 1000ms ease;
    transition:         opacity 1000ms ease;
}
.bootstrap-datetimepicker-widget .dropdown-menu:hover {
    display: block;
    opacity: 1;
}