Controlling child window properties.

In the example: Demos > Tests > MultipleWindows
I would like to create a child window which does not close the main window when closed. The purpose is to have an inspection window which will be created for a short time, then closed, and then something else is inspected. My hunch is that it's something with JFrame if I'm not confused, but I probably am because I can't find anything.

After using the G4P library, I've noticed that after about three to seven windows are created and closed in procession, my entire computer starts going very slowly, but my resource monitor shows nothing specific. So, I'm looking to build the windows from scratch to see if it's any different or if it's my computer.