I have a `handle` to third party window (not created by me, retrieved using the `FindWindow` function). Now I'd kile to create a small popup style window that will ALWAYS be laid down ovev/on top of that third party window. The case is I don't wanna the popup to be always above all the system windows, but ONLY above the window that I've described so I don't wanna use the `HWND_TOPMOST` option in the `SetWindowPos` function.

How can i achieve it without using the `HWND_TOPMOST` flag?