User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0) Gecko/20100101 Firefox/4.0 Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0) Gecko/20100101 Firefox/4.0 I'm not the site listed aboves admin / developer, so the javascript might be slightly odd, but I have noticed that since upgrading to 4.0 the Javascript does not seem to work as on this page as before. Reproducible: Always Steps to Reproduce: 1) Go to http://www.sorting-algorithms.com/ 2) Click the "restart-all" button (the biggest green icon). 3) Watch and wait for all the sorting algorithms to finish 4) Click it again 5) Notice that it resets, but doesn't start them off again. Expected Results: The expected behaviour (and the behaviour in the previous version of Firefox) would be every time you click the button for it to reset and start again from scratch. Note: This is broken for all the green buttons.

Just a quick note: In case it wasn't clear, this is on Firefox 4.0, not the trunk, although there doesn't seem to be a drop down for that version.

I can confirm this with Seamonkey trunk and FF4.0 on win32. Restarting works in Opera11 and the FF safemode doesn't help. Seamonkey shows no errors in the error console. JS Engine is just a guess, please don't throw stones at me if that is incorrect.

Regression 1 window: Works: http://hg.mozilla.org/mozilla-central/rev/5f857be14db9 Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; rv:2.0b3pre) Gecko/20100727 Minefield/4.0b3pre ID:20100728145944 Fails(image is not reset, don't re-run): http://hg.mozilla.org/mozilla-central/rev/b8b62b351c09 Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; rv:2.0b3pre) Gecko/20100728 Minefield/4.0b3pre ID:20100728152620 Pushlog: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=5f857be14db9&tochange=b8b62b351c09 Triggered by: Bug 572520 - make all imgIDecoderObserver notifications asynchronous { Regression 2 window: Fails(image is not reset, don't re-run): http://hg.mozilla.org/mozilla-central/rev/e0ea4e4d401f Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b10pre) Gecko/20110121 Firefox/4.0b10pre ID:20110121024721 Fails(infinite loop): http://hg.mozilla.org/mozilla-central/rev/ac1ddab6de59 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b10pre) Gecko/20110121 Firefox/4.0b10pre ID:20110121152914 Fixed regression 2 window: Fails(infinite loop): http://hg.mozilla.org/mozilla-central/rev/bc2fda9a8b32 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b10pre) Gecko/20110121 Firefox/4.0b10pre ID:20110123202459 Fails(image is not reset, don't re-run): http://hg.mozilla.org/mozilla-central/rev/4e57b18dd908 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b10pre) Gecko/20110123 Firefox/4.0b10pre ID:20110123203513 } Pertially fixed regression 1: Fails(image is not reset, don't re-run): http://hg.mozilla.org/mozilla-central/rev/8149e1a06476 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b11pre) Gecko/20110125 Firefox/4.0b11pre ID:20110126103957 Fails(image is reset, don't re-run) http://hg.mozilla.org/mozilla-central/rev/908ae37abec8 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b11pre) Gecko/20110126 Firefox/4.0b11pre ID:20110126110507 Pushlog: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=8149e1a06476&tochange=908ae37abec8

thanks Alice, the last regression window points to bug Bug 594771 , moving to imagelib

Alon? The site is using animated gifs; it sounds like we're not properly restarting the animation on src set for some reason?

We do call ResetAnimation() on the image. But mAnimationFinished is false, so ShouldAnimate() returns 0 and hence ResetAnimation() does absolutely nothing.

Looks a lot like bug 641198.

Yeah, the patch in bug 641198 fixes this.

I can not reproduce any more http://hg.mozilla.org/mozilla-central/rev/7d4eb3d3c9de Mozilla/5.0 (Windows NT 6.1; WOW64; rv:6.0a1) Gecko/20110419 Firefox/6.0a1 ID:20110419030537 http://hg.mozilla.org/mozilla-aurora/rev/6b33dec92aaa Mozilla/5.0 (Windows NT 6.1; WOW64; rv:5.0a2) Gecko/20110419 Firefox/5.0a2 ID:20110419042005

Thanks for confirming, bug 641198 should indeed have fixed this.