CSS Opacity not working in IE11

That appears to be yet another IE bug.. As a work-around, you could instead add the opacity via the background property with a rgba() color. Then simply add the opacity to the td element.

Updated Example - results seem consistent across browsers.

.faded {
    background-color: rgba(255, 0, 0, 0.4);
    height: 100px;
}
td {
    opacity:0.4
}

If someone else has a problem, it helped me:

.foo {
  opacity: 0.4;
  position: relative; /* for IE */
}

More info