Bug 44529

Created attachment 65283 [details] screenshots and extension A highly reproducible rendering flash occurs on http://cbgb.com/ whenever a Safari extension adds a 'beforeload' listener to the page. It doesn't matter what's in the listener; the problem can be reproduced with a trivial empty listener. Removing the listener eliminates the problem. The site is using jShowoff to rotate through different header images every 8 seconds or so. The initial load of the page is OK, but almost every time the header rotates after that, it will render incorrectly for a fraction of a second as it changes to the next image. The attached zip includes: - header-good.png = screenshot of correct rendering - header-bad.png = screenshot of incorrect rendering - beforeload.safariextension = source of Safari extension to reproduce the problem - beforeload.safariextz = packaged Safari extension to reproduce the problem