* Fix LP: #783790 - Firefox 4 crashes when opening Selenium IDE window. Ignore signals for menus without popups * Fix LP: #783856 - Firefox 4.0.1 Crash Report [@ uGlobalMenuBar::~uGlobalMenuBar ]. Don't bail out of building a menu when encountering a non-XUL element. Also toughen up destructors to not crash if the menuitem never initialized properly * Fix LP: #783997 - Firefox 4.0.1 Crash Report [@ uGlobalMenuBar::ShouldParentStayVisible ]. Don't crash if the window gets destroyed before the panel responds to RegisterWindow