I searched high and low on these forums and couldn’t find any mention of this, so I hope this will be helpful to somebody! 
This code throws an infinite loop error:
IDListener.focusOut = function(eventObject) {
Alert.show("blah blah", "ID Error!", Alert.OK, null, myClickHandler, null, Alert.OK);
};
ID.addEventListener("focusOut", IDListener);
But this code works fine:
IDListener.focusOut = function(eventObject) {
ID.removeEventListener("focusOut", IDListener);
Alert.show("blah blah", "ID Error!", Alert.OK, null, myClickHandler, null, Alert.OK);
ID.addEventListener("focusOut", IDListener);
};
ID.addEventListener("focusOut", IDListener);
Thanks to some random guy on a random blog for figuring this out, I was about to lose my mind! :crazy: