[Seaside] How to change children in a callback?

[Volker Nitsch]

I have a list of bookmarks in a global var "Data current".
All sessions display that and let users add/delete.
Now this changes need to propagate to all other sessions.

Each bookmark is derived from WAComponent, to have its own a callback.
Currently each session is dependant of "Data current" and recreate its
childs on a change.
Problem: In another browser there is a valid bookmark. User clicks "delete".
But on the server that child is already thrown away because of another request.

What i would like:
1) Keep the childs until the next request.
2) Process the callback. Maybe the bookmark-data does not longer
exists, but i want to handle that myself.
3) Check if Data was changed before the callback. If, recreate childs
in this session.
(Or maybe first #3, then #2)

Is there a way to do that, without putting "MySession
callbackProcessed" in every callback?

(Or: Is there a more seaside-way? just beginning.)

--
-Volker

"Any problem in computer science can be solved with another layer of
indirection. But that usually will create another problem." David
Wheeler