Hi folks, AFAIK
the Observer / Observable pattern is dealing with One to Many relations while the Publisher / Subscriber pattern is able (better: Is  made for) Many to Many relations between observers and subjects.
I am actually working on a GUI Framework following the
"Multimedia" Oberon Program Editor "Edit" described in :

Szyperski Write-Ing Applications     (implemented in the Oberon OS)

http://citeseer.comp.nus.edu.sg/szyperski92writeing.html

For the impatient, the Texteditor is THE    GUI Framework, or simply said  : Scintilla is far away from beeing good enough .

*What I would like to know :  Featuring  multiple different VIEWS on the same MODEL including non textual elements like GRAPHS, HYPERTEXT, RUNTIME_ELEMEMTS within an MDI environment ... Does this really requires and Publisher/Subscriber implementation.

Let me try to explain it a bit better, For Instance :
My planned Multimedia Editor  contains 2  classes their graphical representation (UML f.i.) modul dependencies, http links, EBNF visualisation an DSL Interpreter... may be they are sharing one window, may be the are splittet.Modifying something should/could have an direct impact to everything else.
Can Observer based Signal/Slot do that for me, or is in this case the publisher/subscriber pattern the preferable implementation ?

Opinions, hints, ideas  are Welcome
Many thanks in advance, Bjoern