66184 2011-08-13 02:15:14 -0700 Pages with border-collapse and RGBA borders have very bad scrolling performance 2015-03-25 21:59:25 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Mac OS X 10.6 RESOLVED WORKSFORME http://chadvonnau.com/projects/web/examples/webkit-table-bug/bordercollapse.html P2 Normal --- 1 chad zalan ap jonlee simon.fraser zalan oldest_to_newest 450826 0 chad 2011-08-13 02:15:14 -0700 I've made some examples to demonstrate some performance bugs with table rendering. These examples are the same content with different styling: 1) Normal scrolling. Solid borders and border-collapse:separate http://chadvonnau.com/projects/web/examples/webkit-table-bug/index.html 2) Slow scrolling. Solid borders and border-collapse:collapse http://chadvonnau.com/projects/web/examples/webkit-table-bug/bordercollapse.html 3) Very slow scrolling and beach ball of death. Semi-transparent RGBA borders and border-collapse:separate http://chadvonnau.com/projects/web/examples/webkit-table-bug/rgbaborders.html I'm testing with Safari 5.1 and OS X 10.6.8 (+update) on my Late 2006 MacBook Pro. Firefox 4 sees roughly equal performance on on all of those examples. Safari 5.0 and earlier sees about the same performance on each example. Chrome 13.0.7 has similar performance issues with these examples. I reported what I believe to be the same issue to Google several months back. Here's my bug report with google: http://code.google.com/p/chromium/issues/detail?id=68215 Perhaps these issues may be coming from webkit code that Google has been using for a few months but only made it into Safari in 5.1. Here is another page that exhibits performance problems because of border-collapse:collapse http://panlex.org/u 450829 1 chad 2011-08-13 02:40:34 -0700 *** This bug has been marked as a duplicate of bug 34649 *** 450839 2 simon.fraser 2011-08-13 07:56:30 -0700 Reopening; the other bug is about DOM access. 466950 3 chad 2011-09-14 02:42:04 -0700 Thanks, Simon. The two bugs seem related from my naive perspective. Was thinking this one might get resolved faster if it was merged with a bug that already had other people involved. 1079632 4 ap 2015-03-24 09:52:29 -0700 This appears to work nicely in current shipping Safari (I tested with Safari 7.1.4). 1080160 5 simon.fraser 2015-03-25 19:08:34 -0700 I bet this scrolls horribly if it's changed to use overflow: scroll. I think we've regressed table border performance.