Weird behavior in Chrome with HTML select

Question

I have a CSS menu pretty simple, that's show an list UL on hover. From a time ago, in Chrome, when I select an option that is on the same position as the menu that's hidden by display: none, I get the menu hovered.

How a select option can hover a hidden object on click? This only happens on Chrome.

I tried to change select z-index to a higher. Changed z-index for menu to -1 until parent ul get hovered, but no success, still get the issue

Here is a code

Try select the option test5:

ul.menu ul {
    display: none !important;
}

ul.menu li:hover>ul {
    display: block !important;
}

ul.menu ul {
    position: absolute;
    left: -1px;
    top: 98%;
}

ul.menu ul ul {
    position: absolute;
    left: 98%;
    top: -2px;
}

ul.menu, ul.menu ul {
    margin: 0;
    list-style: none;
    padding: 2px;
}

ul.menu li ul.links {
    margin: 0;
    list-style: none;
    padding: 0;
    border-color: #AAAAAA;
    border-width: 1px;
    border-style: solid;
}

ul.menu ul.links li {
    margin: 0px;
    list-style: none;
    padding: 2px;
    background-color: #F5F5F5;
    background-repeat: repeat;
}

ul.menu table {
    border-collapse: collapse;
}

ul.menu {
    display: block;
    float: left;
}

ul.menu ul {
    width: 160.65px;
}

ul.menu li {
    display: block;
    margin: 0;
    font-size: 0px;
    margin-right: 4px;
}

ul.menu a:active, ul.menu a:focus {
    outline-style: none;
}

ul.menu a, ul.menu li.dis a:hover, ul.menu li.sep a:hover {
    display: block;
    vertical-align: middle;
    border-width: 0px;
    border-color: #6655ff;
    border-style: solid;
    text-align: left;
    text-decoration: none;
    padding: 3px;
    font-family: Arial, Helvetica, Verdana;
    font-size: 11px;
    color: #000;
    text-decoration: none;
    cursor: default;
    border: 1px solid transparent;
}

ul.menu ul.links a {
    display: block;
    vertical-align: middle;
    background-color: #F5F5F5;
    border-width: 0px;
    border-color: #6655ff;
    border-style: solid;
    text-align: left;
    text-decoration: none;
    padding: 4px;
    font: normal 11px Verdana;
    color: black;
    text-decoration: none;
    cursor: default;
    border: 1px solid transparent;
}

ul.menu span {
    display: none;
    overflow: hidden;
}

ul.menu li {
    display: block;
    float: left;
}

ul.menu ul li {
    float: none;
}

ul.menu ul a {
    text-align: left;
    white-space: nowrap;
}

ul.menu li.sep {
    text-align: center;
    padding: 0px;
    line-height: 0;
    height: 100%;
}

ul.menu li.sep span {
    float: none;
    padding-right: 0;
    width: 5px;
    height: 16px;
    display: inline-block;
    background-color: #AAAAAA;
    background-image: none;
}

ul.menu ul li.sep span {
    width: 80%;
    height: 3px;
}

ul.menu li:hover {
    position: relative;
    z-index: 999999;
}

ul.menu li:hover>a {
    text-decoration: none;
    border: 1px inset #CCCCCC;
    background: #E3E3E3;
    border-radius: 3px;
    -webkit-border-radius: 3px;
    -moz-border-radius: 3px;
}

ul.menu li a:hover {
    position: relative;
    text-decoration: none;
    border: 1px inset #CCCCCC;
    background: #E3E3E3;
    border-radius: 3px;
    -webkit-border-radius: 3px;
    -moz-border-radius: 3px;
}

ul.menu ul.links li:hover>a {
    background: #F8FBFE;
    text-decoration: none;
    border-radius: 1px;
    -webkit-border-radius: 1px;
    -moz-border-radius: 1px;
    border: 1px solid #BAE3FE;
}

ul.menu ul.links li a:hover {
    background: #F8FBFE;
    position: relative;
    text-decoration: none;
    border-radius: 1px;
    -webkit-border-radius: 1px;
    -moz-border-radius: 1px;
    border: 1px solid #BAE3FE;
}

ul.menu li.dis a {
    color: #AAAAAA !important;
}

ul.menu img {
    border: none;
    float: left;
    _float: none;
    margin-right: 4px;
    width: 16px;
    height: 16px;
}

ul.menu ul img {
    width: 16px;
    height: 16px;
}

ul.menu img.over {
    display: none;
}

ul.menu li.dis a:hover img.over {
    display: none !important;
}

ul.menu li.dis a:hover img.def {
    display: inline !important;
}

ul.menu li:hover > a img.def {
    display: none;
}

ul.menu li:hover > a img.over {
    display: inline;
}

ul.menu a:hover img.over,ul.menu a:hover ul img.def,ul.menu a:hover a:hover ul img.def,ul.menu a:hover a:hover a:hover ul img.def,ul.menu a:hover a:hover img.over,ul.menu a:hover a:hover a:hover img.over,ul.menu a:hover a:hover a:hover a:hover img.over {
    display: inline;
}

ul.menu a:hover img.def,ul.menu a:hover ul img.over,ul.menu a:hover a:hover ul img.over,ul.menu a:hover a:hover a:hover ul img.over,ul.menu a:hover a:hover img.def,ul.menu a:hover a:hover a:hover img.def,ul.menu a:hover a:hover a:hover a:hover img.def {
    display: none;
}

ul.menu a:hover ul,ul.menu a:hover a:hover ul,ul.menu a:hover a:hover a:hover ul {
    display: block;
}

ul.menu a:hover ul ul,ul.menu a:hover a:hover ul ul {
    display: none;
}

ul.menu span {
    display: block;
    background-position: right center;
    background-repeat: no-repeat;
    padding: 0 2px 0;
}

ul.menu ul.links span {
    background-image: url(./images/arr_nav.gif);
}

ul.menu ul.links a:hover span,ul.menu table a:hover a:hover span,ul.menu table a:hover a:hover a:hover span {
    background-image: url(./images/arr_nav.gif);
}

/* DHTML WINDOW */
.dhtmlwindow {
    position: absolute;
    border: 1px solid rgb(153, 153, 153);
    #border-color: rgb(142, 153, 186);
    #border-color: rgba(142, 153, 186, 0.3);
    visibility: hidden;
    background-color: #fff;
}

Answer 1

It appears to be a bug in Chrome only, I could not replicate in FF.

Try adding these 2 lines they worked when I tried them out in your Fiddle.

ul.menu li {pointer-events: none;}
ul.menu:hover li {pointer-events: auto;}