Noticed a bug on my Safari after upgrading to Lion. Haven’t been able to recreate it is as it appears to be random, when using Safari and you close some tabs. When you try to quit the Safari, the option is greyed out from the Safari Menu and Command+Q does not work. If you try to restart your mac you’ll get the screen shot below.
So far there doesn’t seem to be a patch in place and temporary solution so far is to Force Quit Safari. You can also delete the Safari icon on the dock and add it back. Will keep updating this post still a permanent solution is found or is patched by Apple.