It seems to be related to some script crashing in the background. A few seconds after the video stalling in full screen, if you alt+tab you can see a "A script has stopped" dialog from Firefox.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/677262 Title: Flash player fullscreen completely crashes Ubuntu To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/adobe-flashplugin/+bug/677262/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs