Box :
=====

   Boxes represent (sub)processes. A box is a rectangular frame, which
may contain ports on its periphery (see help:Editing:Ports).
 
  How to create a box:
1- select the "edition:box:create" menu function.
2- drag the mouse left button from opposite
   corners in the drawing area.

   Box select/move/kill functions apply to its attached ports
altogether.

   Proper nesting of boxes, and absence of overlapping, is NOT checked
until explicit translation/completion is required by the user.

   Boxes can be reshaped or rescaled from any corner, using the
Edition:box:reshape/rescale functions. In the first case ports are
projected orthogonally, while in the second case they keep proportions
along the side of the box.  Reshape may abort when ports would project
outside boundaries.


 Box size attributes can be fixed by resources :
           atg*boxLineWidth: 3
           atg*boxMinWidth:  10
           atg*boxMinHeight: 10