After talking with some users about the usability of the AS3-Layout-Framework, I realized that the dynamic layout approach (layout strategies totally independent from containers) seemed to be a bit confusing or too complicated.
To prevent this issue, I choose the approach of concrete containers like in C#. Now, every container has its own layout strategy implemented. F.e. an HBox can layout its child components horizontal and a FlowBox can also align them in a specific way.
With regard to a gui-system on top, this approach has its advantages (first of all simplicity).
During the next days, I will adapt the old class diagrams and update the repository.
The source code is available here