I've recently been experiencing a problem where session restore does not restore all my lost windows after a Firefox crash. Since this started occurring, my "Recently Closed Windows" History submenu will not open - although the option isn't greyed out, the menu doesn't display and instead I get a tiny blank box anchored at the submenu display point. This originally started occurring on version 32, I am now fully upgraded to version 34.0.5 and the issue still occurs. Restarting Firefox and uninstalling/reinstalling Firefox does not solve the issue, the submenu is still not greyed out but also not displaying properly.