FF4 hangs intermittently with Flash, loses all headers

Question

It usually happens when the Flash object has its buttons below the "fold" and has to be scrolled up to get to them. The scroll button doesn't work, so I click the window and try again. It still doesn't work, so I try the scrollbar, which also doesn't work. By then, I notice that the window has lost everything but the borders, just like a read-only popup but maximized, then it goes translucent, and while it's still spinning its wheels, I may have to hit CTRL-ALT-DEL to get Task Manager to kill it, because even the exit button doesn't always work. Version 3 had some issues, as I recall, but nothing like this.

Answer 1

While I'm at it, I might as well ask why the restart doesn't ask permission to reopen all the sites I had open before, especially in the event one of those sites was the cause of the problem and the page I was on was a mere victim of other circumstances. It's especially annoying to hear several videos playing at the same time, because the pages are opened from scratch, instead of left in the state they were in at the time of the hang.