User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8a6) Gecko/20050107 Firefox/1.0+ (stipe) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8a6) Gecko/20050107 Firefox/1.0+ (stipe) Multiple moving items show visible JS execution lag or dropped frames. Reproducible: Always Steps to Reproduce: 1.Open the attached HTML files 2.Observe the animations. 3. Actual Results: Jitter on multiple object. Expected Results: Smooth 1 pixel movements. DHTML performance as to CPU utilization and DHTML speed has improved greatly in recent months. This bug was posted to illustrate the down side of recent changes. This symptom appeared in Thunderbird trunk builds sometime after 20040409 (last build I have that does not show this symptom) Test platform: P3-s 1.4 G 512m/ ATI radeon 7200 64m DDR WinXP pro sp2 Some additional observations: Display resolution has no affect. Moving images or characters the same is seen. Image size does not change the symptom. The first 2-3 seconds of the animation is smooth, then begins to jitter.

Joe, I can't seem to reproduce this jitter with a current Linux trunk build (P3-733 CPU, Radeon 9000 graphics card). Could you possibly narrow down when this appeared using the 1.8a milestones and builds from http://archive.mozilla.org/ as necessary? The 2004-04-09 date you mention is at the very beginning of the 1.8 milestone cycle; there have been tons of changes since then...

Well after downloading at least 12 Thunderbird trunk builds from the archives, I have not been able to narrow this down any. As a matter of fact, the symptom seems to change somewhat in severity from build to build. Perhaps it is a system specific thing but one thing is sure, the Firefox and Thunderbird builds that came from the Aviary do not produce the problem, and trunk builds do. I have marked the bug as 'minor' and will continue to watch it closely as things change on the trunk, that might affect this.

Joe, did you already discover more?

(In reply to comment #6) > Joe, did you already discover more? The jitter is still observable with WinXP on current trunk builds. Just to confirm that the first 2-3 seconds of the animation is smooth, then the movements start to jitter.

The same "behaviour" is reported in bug 129496 - there are also a few examples where you can test (see comment #19 there), maybe most visible at http://3dhtml.netzministerium.de/examples/solarsystem3d.html

I can see the bug especially with the "2 dots" example. With my build with the "What I backed out" patch from bug 280922, it seems much smoother.

For me, this working very nicely now that bug is fixed. Joe, could you please test again with the latest trunk build? ftp://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk

Also working great for me now that the nsIThreadManager stuff landed.

Same results for me, very smooth, marking FIXED (by bug 326273). Please reopen if you disagree