I understand how to group containers and create a layout
based on constraints, but what I'm having trouble finding is
documentation on how to create such a layout that a user can, for
example, drag the edge of a container to change its size and have
all the neighboring containers resize accordingly. Is there anyone
who has done this before? Would you point me to some code? Or
better, just the key components and concepts necessary to create
such a layout? Thanks!