If an iframe has a z-index of 0, certain elements from the outer page will show up on top of the iframe contents if an element inside the iframe is put into fullscreen. Behavior can be seen on: http://www.behance.net/gallery/Andrey-Pratama-Showreel-2012/8010347 If the z-index of the iframe is changed to 1, it works as expected.
Created attachment 197389 [details] Screenshot of the iframe element in full screen
Brad, can you try a WebKit nightly? We recently fixed a full screen bug involving <iframe>s and stacking layers.
Specifically, this was reported in bug #111637 and fixed in <http://trac.webkit.org/changeset/145001>,
Indeed it is fixed. Sorry about the duplicate. *** This bug has been marked as a duplicate of bug 111637 ***