78943 2012-02-17 16:20:32 -0800 Avoid compositing empty elements 2012-03-14 14:32:46 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Unspecified Unspecified RESOLVED DUPLICATE 63499 P2 Normal --- 1 wangxianzhu wangxianzhu enne jamesr klobag simon.fraser vangelis wiltzius oldest_to_newest 559632 0 wangxianzhu 2012-02-17 16:20:32 -0800 Google+ has a zero-height fixed-position element beneath the main content. we enable compositing for fixed-position elements, which means lots of content divs overlap it and are also composited. -- husky@chromium.org 563278 1 wangxianzhu 2012-02-23 11:15:45 -0800 Just verified that the patch of bug 78186 also fixed this bug, because an empty rect doesn't intersect any other rect. 563601 2 wangxianzhu 2012-02-23 15:59:46 -0800 Sorry my previous verification was not complete. Bug 78186 can prevents empty fixed position element that is at the bottom layer from being composited (and in turn may prevent elements over it from being composited). If an empty element is over another composited element, it may still be composited because the intersect condition change in bug 34065. Would it be better to fix issue of cliprect cache instead of changing the overlap checking for bug 34065 that will cause unnecessary compositing layers? We also tried to disable cliprect cache, and didn't see visible performance change. 578782 3 wangxianzhu 2012-03-14 14:32:46 -0700 *** This bug has been marked as a duplicate of bug 63499 ***