I've been trying to diagnose this one for a week now and I've done all but pull my hair out over it. I run a very basic, bare bones setup that has always been rock solid for as long as I've been using FireFox. The machine is: Windows XP SP3, Firefox 11, Flash 11.9. Addons are: Adblock Plus 2.1.2, Adblock Plus Pop-up 0.4, Flash Video Downloader 3.9.3, Status 4 Ever .17, Password Exporter 1.2.1 But out of the blue, plugin container will freeze for 30-45 seconds if I press the back button on my MOUSE while hovering over a YouTube video. I can either sit and wait the 30-45 seconds and plugin container will crash and the browser will start moving again, or I can forcefully stop the process in task manager. This is ONLY on YouTube videos, on their respective pages and does not happen on embedded videos on other websites. Every other flash video site from Hulu to adult work fine. And when I say hovering over the YouTube video I mean literally, if one pixel of my mouse pointer is touching the video and I press back on the mouse, it freezes the entire browser. If I alt+left arrow it's fine. If I press back on the browser button it's fine. If I click the back button on my mouse while hovering anywhere else on screen, it's fine. The only "solution" I've found is setting dom.ipc.plugins.enabled to false in about:config. But this is not a real solution for me, as I need dom.ipc.plugins.enabled set to TRUE in order to keep functionality in other things and it just straight up messes up little things all over other webpages when it's off. I have tried every possible combination of solutions I can think of and have no clue what to do next except switch browsers. This is what I've done so far: · Disabled protected mode for flash in FireFox · Disabled hardware acceleration in FireFox AND Flash · Uninstalled/Clean installed every version of Flash down to 11.1 · Disabled all addons · Uninstall/Clean installed FireFox 11 and ran it fresh · Uninstall/Clean installed FireFox 26 and ran it fresh · Updated mouse drivers · Ran without mouse drivers · Changed USB port mouse was in · Did all of these same changes on my Windows 7 partition, still freezes/crashes I don't know what else to chalk this up to other than it being a direct problem between the plugin container process and something that YouTube has changed in the backend recently that the masses would never see. Is it possible there's some hotkey being assigned to the mouse back button within YouTube's video player now, and when pressed it kills the plugin container? Doubtful but I'm at the bottom of barrel here. Any information would be helpful, thanks.