example: div { display:none; opacity: 1; -webkit-transition: opacity 1s linear; } div:hover { display:inline; opacity: 0; } The webkit-transition does not work in the example above. This is commonly used for modal overlays.
Right, transitions don't work if the element is changing from one display type to another.
I assume this is covered by the transitions spec? Do other browsers agree? Marking WONTFIX for now per Simon's comment.