I have created a class let's call addCustomer that extends JPanel.

In my "main" program class, I can call addCustomer and add it to my
main JFrame, however, what I wish to do is create a JButton and when
the button is pressed, I want the addCustomer form to pop up in it's
own "Window".

I'm sort of new to swing, so I'm not sure how to proceed. Any ideas?