Tested with #701 and #816.
You may need this plugin if you sometimes close IDEA by accident. When you want to exit, you'll see a confirmation dialog with countdown. You can cancel the dialog (if you changed your mind or it was by accident) or you can click on "Exit Now". If you do nothing, after some time (by default it's two seconds) IDEA will be shut down.
http://www.intellij.net/tracker/idea/viewSCR?publicId=2883 ("Shutdown warning")
http://www.intellij.net/forums/thread.jsp?forum=3&thread=2265&message=31410 ("Exit application confirmation")
http://www.intellij.net/forums/thread.jsp?forum=3&thread=6365&message=213387 ("Shutdown Idea")