I've developed a WinForms application that allows users to create a number
of child forms within a larger parent form. The child forms can be dragged
around within the bounds of the parent. They can also be resized.

When the user closes the application, I want the size and position of the
child forms to be persisted. I've figured out how to do this. The only thing
I'm lacking is the z-order. How do I determine the z-order of each child
form relative to its siblings? If I could find a way to persist this
information, then when the app starts up again, I could arrange the forms
with the same z-order that the user used in the previous session.

Thanx..