I don't know IB well enough but according to the documentation at
http://docs.sun.com/db/doc/802-2110/
6i63kq4sk?a=view#03.Working_with_Interface_Builder-98
it supports a different (but not necessairly insufficient) way of
specifying autoresize/autolayout constraints than GS[HV]boxes used in
Renaissance. Probably it is one of the main obstacles to using Gorm to
edit Renaissance files. I wonder what are the defficiencies of the
existing mechanism supported by IB/Gorm for autolayout (implemented by
aligning unarchived objects using the specified constraints after
unarchiving) and if there was any advantages adopting this mechanism in
Renaissance. Or the other way around: what about adopting boxes in
Gorm.
Boxes are simpler for a programmer creating the UI programmatically,
but
the spring/rope analogy of IB might be more intuitive for visual UI
designers and more easily/cleanly representable in a graphical editor.