Summary: After navigating back and forth through the b/f cache, the web view is set to "copy on scroll" despite having content that should prohibit such behavior (e.g. fixed background). To reproduce: 1) Go to <http://www.w3.org/TR/CSS21/>. 2) Click on the "next" link. 3) Go back. 4) Go forward. 5) Scroll up and down. Expected result: The "W3 Working Draft" banner on the left to remain fixed and not scroll out of view. Actual result: The "W3 Working Draft" banner scrolls out of view when scrolling down, and artifacts appear when scrolling up. Regression: Yes, this doesn't happen in shipping Safari. Notes: While this is a rendering bug, it's ultimately caused by the page loading machinery not (re)setting up the view properly, so I'm filing under Page Loading.
<rdar://problem/5061030>
Regressed in <http://trac.webkit.org/projects/webkit/changeset/13440>.
Actually the regression in r13440 was fixed in r13649 (fix for bug 8079). It came back later.
Most recently regressed in <http://trac.webkit.org/projects/webkit/changeset/15722> (fix for bug 10179).
Created attachment 14415 [details] Keep the slow repaint object count intact and non-negative
Comment on attachment 14415 [details] Keep the slow repaint object count intact and non-negative r=me
Landed in r21329.