[Urwid] event detection question

[Eric S. Johansson]

I've got most of my code working but I'm puzzled by how to solve one 
problem.  If the user has been editing data in an edit field, how do you 
know when they're done?  A good enough definition of done is whenever 
they pressed another button be it a radio button or some other command.

problem being, I would need to detect button presses outside of the 
radio button group.  I can stuff code into each callback for every 
button to capture the edited data, but I would hope there is a solution 
isn't quite so prone to errors.

thanks in advance
--- eric