First of all, thank you for the reply.
Here is the problem:
Let's say there is a dynamically built edit form (which is only a piece of the Asp.Net web page) and there are two main requirements to its layout:
1. It must adjust to browser window size;
2. End user need to have an ability to customize layout of the form. (Under such customization I mean ability to hide/reposition controls and group them using predefined containers such as Tab Control, collapsable panel etc.)
I have been considering your control to give end users more flexibility in adjusting layout to browser viewport size.
As far as I see, to have my approach work I need to use standalone WebLayout control inside each of the predefined containers and resize this control manually with javascript so that it fits parent container. The same is valid for the outermost WebLayout that contains entire edit form.