I've been noticing a number of problems with Flash in Firefox v20 and 21 that don't occur in Internet Explorer. I don't use any other browsers. The problems also seem to sometimes be site-specific, other times not. 1) Fox News ONLY - Videos will play then suddenly pause and say "buffering" but never restart. However, if you move the timeline slider back a few seconds it will pick up and continue as though nothing ever happened. 2) Fullscreen separation - When watching fullscreen videos, toggling in and out of fullscreen can cause the fullscreen feed to become divorced of the browser and behave on its own. In one instance, with the browser window maximized you could see the fullscreen video through the transparent borders of the window playing behind the browser window. Minimize the browser window and the video minimizes with it. Resize the window and the video is no longer visible. But in all three states, the video keeps playing, and returning to maximized the video is still visible through the screen border. 3) Video playing autonomously - I had one instance where not only did the video get separated from the browser, but continued streaming even though Firefox had been closed entirely and no longer showed up in the process list. Yet you could still hear the video playing despite having no video, window, or controls to stop it. I eventually stopped it by ending the plugin container processes. 4) Hulu only - During the intros to a show, and sometimes even during a show, switching to fullscreen mode causes the video to freeze. This requires a reload of the page to restart the video, waiting for the intro to pass, and resize once the show proper is playing. 5) Hulu only - Another strange behavior on Hulu is a stall similar to what happens on Fox News, though it seems to only affect commercials. They just stop playing, and hitting the "10 second rewind" restarts the video and it continues without further issue. All in all, I'd like to blame the individual website's player functions, but the common threads are Flash and Firefox. And I've had no problems like this under IE. All my graphics drivers are up to date, Windows patches, etc. So I'm at a loss as to what's going on.