Popup aggravation - help needed

I’m having a problem destroying a pop-up.
The window creates beautifully, but does not close on click of the ‘x’.

Any and all help appreciated.

Here’s the code

buttonListener = new Object();
buttonListener.click = function(){
  myWindow = mx.managers.PopUpManager.createPopUp(_root, mx.containers.Window, true, { closeButton: true, title:"Change Password", contentPath:"test_mc"});
advanced_btn.addEventListener("click", buttonListener);
closeWin = new Object();
closeWin.click = function(){
myWindow.addEventListener("click", closeWin);