i switched to creating all my callbacks programmatically, so i handle all errors in the function that creates the callback
this is useful mostly for logging the errors (i found that exceptions in callbacks fail silently otherwise ,due to that suppress exceptions flags in a multi page app)
if there is a way of firing an event from within a callback and by that updating another output component (not the one used in the callback definition, that would solve the issue of displaying the error to the end user