Addressing application "Quit" options becoming nonfunctional
You may run across a problem with some applications where it will not quit. When you use the command-Q hotkey the application neither responds nor shows any error, and if you go directly to the application menu you will see the "Quit" option is greyed out.
http://reviews.cnet.com/8301-13727_7-20006218-263.html?part=rss&tag=feed&subj=MacFixIt