Form Leave Data Capture

I'm working on a C++ .net app.

I need to detect when a user leaves a form so I can capture changes that were made. I tried using the Leave event to perform the data capture. This works if the user clicks on another form or button, but it does not work if the user selects the menubar and displays a dialog window. MouseLeave doesn't help either.

How can I detect when the user leaves the form?

Thanks,

RudyS