hi thundercadeWell if i want to change the containers height because of design changes. In this case it would not be to hard but with more complex design with cascaded boxes etc. Let's say container is a box which hasn't got a fix pixel-height but takes 20% of the body height...The point is I had some designs where I put it in the end with all fix heights, like you suggest. Then if there was something to change, like adding some pixels to the top-boxes height...I had to change all heights of the childs, childs chils, and so on...