Can cards in a stack be of different sizes

[Russell]

Hi people

What got me started on this different size windows here. I decided as an exercise in design I would emulate a window off the application I was on.  

Now if I wanted duplicate this application a good place to start would be off the menu.  And each procedure off the menu collects information and sets about doing what it was designed to do. (In my case the Print window)  It seems to me that this procedure is what dictates the size of the window needed

I am not thinking like everyone else here on the need for different size windows in an application (stack)
How can an application be constrained to one 5x8 or whatever size window. ?

Thanks

Russell