I'm confirming this as I experienced the same thing. I'm guessing some type of hidden window is created that fills/covers the screen.
** Changed in: firefox (Ubuntu) Status: Incomplete => Confirmed -- Firefox freeze all sistem https://bugs.launchpad.net/bugs/593206 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs