> Now I need to know how to do user defined events such
> that when a digit overflows or underflows the next digit in line receives an
> event and can increment or decrement itself. The event can go direct or
> probably more sensible to send it to the parent which is my top level
> display class not the alignment morph. Any hints appreciated.

I don't know whether I correctly understand what you are trying to do, but one
suggestion would be to maintain a pure domain (the single number) and just let
the UI display each digit..