Hi Henri,
Search Google for "liquid tables", a concept where part of your table has a fixed width (the navigation areas for example) and the rest of the page flows with the size of the Window.
This is really a design and coding feature, and not necessarily a IDE feature. You don't tell a program to "design a page that flows on the monitor", although Dreamweaver supports all the features you need to create a page using liquid tables.
The bad part about Liquid Tables is that they, well, use tables. Using tables for layout is considered bad practice these days, and you should really try to use CSS for these kind of lay out techniques.
If you search Google for "two column layout and CSS" you'll find lots of examples, including this simple one:
http://realworldstyle.com/2col.html
Cheers,
Imar
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Imar Spaanjaars
Everyone is unique, except for me.