Screenr screencasts (for example: http://www.screenr.com/oPis) doesn't work in Firefox Nightly (12.0a1 2012-01-31) but it works in Firefox beta 10.0 (and Chrome) on the same machine (Linux x64). Tested in safe mode with all extensions disabled. In ff beta the video displays the first frame of the screencast which is displayed in the background and it starts playing when pressing play. In Nightly It is just a black background and nothing happens when pressing play.

WFM: Mozilla/5.0 (X11; Linux x86_64; rv:9.0.1) Gecko/20100101 Firefox/9.0.1 Mozilla/5.0 (X11; Linux x86_64; rv:10.0) Gecko/20100101 Firefox/10.0 Mozilla/5.0 (X11; Linux x86_64; rv:11.0a2) Gecko/20120131 Firefox/11.0a2 Reproduced: Mozilla/5.0 (X11; Linux x86_64; rv:12.0a1) Gecko/20120131 Firefox/12.0a1 Last good nightly: 2012-01-12 First bad nightly: 2012-01-13 Pushlog: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=8ffdb4c7404a&tochange=964b118ac852

The first bad revision is: changeset: 84303:65da0d7b408d user: Fabien Cellier <fabien.cellier@gmail.com> date: Wed Jan 11 14:38:19 2012 -0500 summary: bug 410904 : add referrer in http request from npapi. r=josh https://hg.mozilla.org/mozilla-central/rev/65da0d7b408d

Please retest with tomorrows nightly. We removed the referer on http post initiated by plugins

wfm with Mozilla/5.0 (Windows NT 6.1; rv:13.0a1) Gecko/13.0a1 Firefox/13.0a1 SeaMonkey/2.10a1 The server is IIS, marking as dupe of bug 724465

Clearing tracking noms as this is a dupe of a tracked bug