User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:7.0a1) Gecko/20110601 Firefox/7.0a1 Build Identifier: Mozilla/5.0 (Windows NT 6.1; rv:7.0a1) Gecko/20110601 Firefox/7.0a1 When downloading a file in Nightly, the progress bar glow animation that moves along the progress bar resets every time it increases. Reproducible: Always Steps to Reproduce: 1. Download a file 2. Watch progress bar animation 3. Notice that every time progress bar increases in size, the glow animation is reset to the beginning Expected Results: Glow animation should continue traversing the progress bar even when it is increasing in size.

I made a URL testcase for easy comparing with Chrome :) data:text/html;charset=utf-8,<body%20onload="var%20p%20=%20document.getElementsByTagName('progress');%20var%20i%20=%200;%20setInterval(function%20()%20{%20i%20=%20(i%20+%201)%20%%201000;%20p[0].value%20=%20i;%20},%205);"><progress%20max="1000"%20value="0"></progress>

Still available on 22.0a1 (2013-03-02) [at least on Windows 8]. Could you point to the related commit?

(In reply to Ebrahim Byagowi from comment #5) > Still available on 22.0a1 (2013-03-02) [at least on Windows 8]. Could you > point to the related commit? Fixed in the latest nightly. Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130303 Firefox/22.0 there are a number of good test cases in bug 726144.