Playing an unmodded singleplayer game in Ironman mode. The galaxy has been explored at this point, so it's been going on a while. Previously had no problems, but today I was invited to a federation and when I went to respond I found the message couldn't be interacted with (though it could still be moved around the screen). Figured I would quit out and restart, but then found that although both menu options make the right sounds when hovering over or clicking on them, they no longer have any functionality.