For those who, like me, have had nothing but hassles from Plugin Container in the latest Firefox update, here's how to disable it:
Go to a new tab and type about:config in the address bar.
In the search bar at the top type ipc.
there should be 5 results. Make sure they're set to false, false, false, false, 45.
Plugin Container just crashed on me so hard that Win7 couldn't kill the process. This is the first time i've EVER seen Win7 fail to kill something. I had to restart, and even then it froze Windows trying to kill it as part of the shutdown process. Hard reset ahoy. I find a kind of irony in the fact that a process designed to stop plugins from killing Firefox killed my whole computer.