Scripting approach for a splittable window?

[David Epstein]

Has anybody tried to build a scrollable, horizontally and vertically  
splittable window interface that allows a user to create and freely  
add, delete, and edit graphic objects or fields in any pane of the  
window?  The true "page size" might be much bigger than can be shown  
in the window at any one time, but the objective is to let the user  
split his view and inspect any 2 vertical regions and any 2  
horizontal regions (as in a spreadsheet).

I can think of various ways this might be approached, and wondered if  
anyone has experience or advice.  Should we make 4 groups with  
identical content, adjust their scroll properties appropriately, and  
when a user edits one group automatically change all the others (and,  
in that case, should this be done by copying a created or modified  
object, or by replacing each entire group with a copy of the changed  
one)?  Should we maybe keep a "master" page off screen entirely, and  
copy objects from that master page to the appropriate pane by  
checking the rect of each object against the pane's intended scroll  
position?  Or should the "master" set of objects be alternately  
hidden, shown in a pane, or cloned in several panes, based on a list  
of their "logical" locations that gets compared with the intended  
pane scroll positions?  Or should we maybe construct each pane from  
an image of a rect of the master page, and when the user tries to  
edit a pane swap in the real objects, or a scrolled view of the  
master page?

Or something else entirely?

Many thanks.

David Epstein