I've read all the articles and it was really interesting, thank you for that. I'm still little bit confused of it. Even when I'm using the default mapmode MM_TEXT, there is the viewport and the window with predifined parametrs.
What I don't understand is, how is it possible, that I can draw behind the boundaries of the window and during resizing the window I see them... I thought, that there is limitted size of the area (viewport), where I can draw.

And another thing, using the origins of the window, its easy to scroll, so why is it not used for example for the scrollbars and the scrollbars use the ScrollWindow fce and you have to set all the things around it... this is much simpier...