Hello Grant,
with invoking layout() it works well now.
Due to a very long method when creating all the stuff inside the
composite (about 100 labels and other stuff) i desided to break it into
smaller pieces. Each piece is a composite holding certain stuff
regarding one theme. In the original composite i place all the other
composites.
In the main (original) composite invoking layout() works fine, it uses
all the space, but all interior composites do not. I want them to use
the complete width and the needed height. For the height i can use
computeSize, even not in the composite with the image, but this is no
problem. the width should be the width of the main composite. But
setSize does not work. So i ask myself what is setSize for?