No overflow overlay support

There is a CSS property overflow. One of the possible values it overlay. It works the same way as auto but renders the scrollbars over the element content.

jQuery UI handles overflow: overlay like overflow: visible. For example, a plugin instance like this

$element.parent().css('overflow', 'overlay');
$element.draggable({scroll: true});

Won't scroll the parent when the element is dragged.

Demo: https://codepen.io/TheFinesse/pen/RwaPGQZ. See it in Chrome. The bug is not reproduced in browsers that don't support overflow: overlay.

The expected behavior is to treat overflow: overlay exactly like overflow: auto. Maybe there are similar issues with other components.