Whenever none of my preferred wifi networks is available and my Airport is turned on a dialog appears that shows all the available networks at the moment. That is as expected.
However, when I exit that dialog as I don't want to connect to a wifi network, it dissappears, the Airport menu icon shows that it's looking for networks again and the dialog appears again. This is annoying.
How can I prevent the dialog from appearing a second time? Turning off the dialog completely would be viable as well as I almost never use it anyway and can have the same functionality through the Airport menu item.
I'm on a MacBook Pro 5,3 (Mid 2009) with Mac OSX 10.8.4.