Webkit border radius combined with css3 translate3D bleeding

Question

I'm struggling with a problem on Webkit based browsers where if I add a border radius to a div and then apply -moz-translate3d to a ul inside (this is because on the original example I'm using flexslider slideshow), the border radius does not apply and bleeds through the container.

To clearly understand what I'm talking about here's a fiddle example about the problem. If I remove the translate3d property, the border radius is applied.

HTML:

<div class="wrapper">
    <ul>
        <li>
            <div class="caption"><p>Test</p></div>
        </li>
        <li>
            <div class="caption"><p>Test</p></div>
        </li>
        <li>
            <div class="caption"><p>Test</p></div>
        </li>
        <li>
            <div class="caption"><p>Test</p></div>
        </li>
    </ul>
</div>

CSS:

.wrapper {
    border-radius: 20px;
    position: relative;
    width: 500px;
    height: 200px;
    overflow: hidden;
}

.caption {
    position: absolute;
    bottom: 0;
    left: 0;
    background-color: rgba(0,0,0,0.8);
    padding: 2rem;
    -webkit-box-sizing: border-box;
    width: 100%;
    height: 3rem;
    color: #fff;
}

ul {
    width: 800%;
    -webkit-transform: translate3d(-500px, 0, 0); 
}

li {
    float: left;
    width: 500px;
    height: 200px;
    background-color: #000;
    position: relative;
}

.caption p {
    color: #fff;
}

http://jsfiddle.net/R5L3K/12/

Tested it both on Chrome latest version on Mac and Windows.

Thanks in advance!

Answer 1

I have answered this question before. It is a webkit bug.

Add this code to the same selector you are adding border radius too

-webkit-mask-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAA5JREFUeNpiYGBgAAgwAAAEAAGbA+oJAAAAAElFTkSuQmCC);

http://jsfiddle.net/R5L3K/14/

Old answer source flexslider border-radius does not wrap image in Chrome, Safari, but will in Firefox