Berts for Users, Denoument

[Marc Stiegler <marcs>]

In response to Kelvin on Undo, and in response to all the discussion 
of Saves and Berts:

In terms of when to discard an Undo chain, I believe Autocad's 
Undo is indeed better than my earlier proposal. The Xanadu approximation 
of closing a file is closing the window on the document. So rather 
than pitching Undo chains when the user Saves, we should pitch 
Undos when the user closes. I don't think we should pitch the 
whole chain, however--just pitch the chain prior to the most 
recent Save (and if the user's last action was a Save, pitch 
before the prior Save).

We all agree that a graphical representation is best. Graphical 
is in Release 1.1. 

I think we can document Trace Forward/Trace Backward and Undo 
easily. If it turns out during Beta testing that I'm wrong, we 
can implement the "right" solution immediately. But considering 
how much longer software usually takes than we predict, saving 
ourselves an apparent couple-day hack could easily save us a 
month in shipment date.

--marcs