How to override the Netbeans Platform (x) button or the netbeans platform default close operation

Hello everyone, I've been using NetBeans Platform for a little while now and I've run into a problem of handling unsaved changes when the (x) button in the upper right hand corner is clicked to exit the app.  

I've tried adding WindowAdapters to the WindowStateListener and WindowListener, as well as overriding the installers closing() method but the app still just exits immediately.  :? 

What is the proper method for overriding a Netbeans Platform app's default exit behavior?  

Thanks!    :)