User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5) Gecko/20031007 Build Identifier: BuildID:2003120808 Since Mozilla 1.6 beta till the latest Nightly Build of 1.7 of 2003-03-03 Mozilla becomes extremely slow while the www.tweakers.net menu is on screen on one of my computers (The others work fine). Mozilla 1.6 Alpha, 1.5 Final and prior versions do not have this problem. When I'm visiting www.tweakers.net the mouse becomes unresponsive and scrolling becomes slow. As soon as the menu is not on the screen anymore (when I scroll down) the problem disappears. I have two installations of Windows 2000 SP4 (Fully Updated) on the offending computer, one of them does not have any programs installed. Only drivers and Mozilla. Both installations have the same problem. Reproducible: Always Steps to Reproduce: 1. Install Mozilla 1.6 Beta or later 2. Go to www.tweakers.net using my system 3. Then the problem appears Actual Results: The computer became extremely slow Expected Results: It should stay about as responsive as it was in Mozilla 1.6 Alpha or earlier. The system specs of the computer which shows the problem: Chaintech Zenith CT-7NJS Ultra (Onboard E-IDE Serial ATA RAID 0) (Onboard 10/100 Mbit LAN Ethernet) AMD Athlon XP 2600+ - 333MHz Front Side Bus 2x Kingston ValueRam 512 Mb PC2700 333MHz DDR-SDRAM Modules Dual Channel 3dfx Voodoo5 5500 64Mb Creative Soundblaster Audigy 2 Player 2x 120 Gb Serial ATA Maxtor DiamondMax Plus 9 in RAID 0 IDE DVD-ROM LG GDR-8161B 16x48x IDE CD-BURNER Mitsumi 32x12x40x

Well, I'm seeing a dramatic improvement with trunk (1.8a) builds at/after 2004-11-05. I think the patch 243726 has made it better.

Uhm, I meant the patch for bug 243726.

Well, I'm marking this fixed, I'm almost enitrely sure the patch for bug 243726 fixed this bug. I've talked to another guy, who experienced the same problem at http://www.tweakers.net . For him it also improved considerably after the patch for bug 243726 was checked in. It is known that tweakers.net has a lot of hidden absolute positioned divs.

It may be worth retesting with tomorrow's builds. I just landed bug 268090, which fixes some over-optimization bug 243726 added.

Ok, tested with 2004-11-19 trunk build. No noticable slow-down, compared to yesterday.