The X icon is not available to quit firefox, and neither is the "force Quit" option. Will not allow me to shut down my computer because firefox is open
go to help menu in Firefox > troubleshooting information > RESET Firefox
this will reset to Firefox default, however you wont loose bookmarks, but will loose addons IF you have any.
if you cannot force quit, you can shut down and restart.
what were you doing on firefox to cause that?
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