As far as I can tell it’s a bug, yes, Safari is rendering intersection where it shouldn’t.
For some time I thought Safari is doing it right by always rendering intersection of elements, but as far as I understand the specs, only elements in the same 3d rendering context should intersect, and that would be children of elements with a transform-style
of preserve-3d
.
So far the only workaround I found (only tested on Windows yet where Safari shows the same behaviour) is to translate the underlying elements away on the z-axis. Without perspective being applied it won’t actually translate, but Safari/Webkit seems to think it does (which probably is because it mistakenly treats the element as if it were in the same 3d rendering context as the actually transformed dialog) and so the elements do no longer intersect.
.effeckt-overlay {
position: fixed;
width: 100%;
height: 100%;
visibility: hidden;
top: 0;
left: 0;
opacity: 0;
-webkit-transition: 500ms;
-o-transition: 500ms;
transition: 500ms;
z-index: 1000;
background: rgba(0, 0, 0, 0.5);
-webkit-transform: translateZ(-1000px);
}
http://jsfiddle.net/eJsZx/5/