But "immediate mode" means you need to write code to create controls. That is the wrong idea, period. You want to be able to create tools to edit dialogs -- and you DON'T want the controls to be based on pixel positions, pretty much ever.

It's not about whether you can do it. It's whether it's useful to do it that way. You've got a cool tech demo, but you're working on something that won't ultimately be useful. Sorry.