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

Hello Steven!

Thank you for your reply, I got it working, but it wasn't what I thought..  You are correct: it is the ModuleInstaller's closing() method that needs to be overridden.  But it turns out that I wasn't checking the correct open file class instance in my ModuleInstaller; I was pointing to an old, unedited instance, so the closing method exited without a dialog prompt to the user (it thought there were no unsaved changes [Embarassed]  ).

Still, it would have taken me a while to revisit the closing() override code since I had assumed at a glance that it was working as I expected if you didn't reply, so thank you again for taking the time to reply!  :D