Just guessing here, but maybe the "Scrolled" container object is the one that needs to get the config update, rather than its "scrolled subwidget" (your "SearchEntry" thing that actually ends up with the updated properties).

I haven't had a lot of practice with this, but IIRC, actions that are invoked on the container object will propagate down to the scrolled subwidgit when appropriate. At worst, you might end up with two separate widget handles to manage: one for the container and one for the subwidget.

Another guess: have you tried calling the 'update' method on the subwidget and/or the container after a config change?